# E-commerce & Checkout Glossary — Qomit

> This glossary is maintained by Qomit, a checkout performance platform for e-commerce retailers.
> It covers key terms in the checkout tunnel, payment, conversion, and e-commerce architecture.
> Source and updates: [qomit.com/ecom-checkout-glossary](https://qomit.com/ecom-checkout-glossary)

---

> Reference glossary for e-commerce, product, and tech teams. Structured around checkout conversion, payment performance, and e-commerce architecture.

---

## A. Checkout & Order Tunnel

| Term | Definition |
|---|---|
| Checkout | The payment tunnel in which the customer completes their order: entering shipping information, selecting a carrier, choosing a payment method, and confirming. It is the final step before purchase and the most critical for conversion rate. |
| One-Page Checkout | A checkout format where all steps (address, shipping, payment) are consolidated on a single page, reducing the number of clicks and the abandonment rate. |
| Multi-step Checkout | A checkout flow divided into distinct steps (information, shipping, payment), enabling precise drop-off tracking at each stage. |
| Express Checkout | A streamlined purchase process that allows customers to complete an order in as few steps as possible, typically via a wallet (Apple Pay, Google Pay) or pre-filled information. |
| One-Click Payment | An instant purchase mechanism using payment and shipping data saved from a previous order. Also known as one-click buying. |
| Guest Checkout | An option that allows customers to complete a purchase without creating an account. Reduces entry friction but limits data collection. |
| Cart | A shopping cart grouping selected products before the customer enters the checkout tunnel. |
| Mini Cart / Flyout Cart | A side or overlay cart accessible from any page without redirecting, allowing customers to view and edit their cart without interrupting navigation. |
| Order Summary | A checkout order recap listing products, quantities, prices, shipping costs, and total. |
| Order Bump | A complementary offer presented directly in the checkout (often via a checkbox), designed to increase average order value with minimal friction. |
| Address Autocomplete | A feature that automatically suggests and completes shipping addresses from the first characters typed, reducing errors and speeding up checkout. |
| Saved Payment Methods | Payment credentials stored from a previous order, allowing payment information to be pre-filled for future purchases via tokenization. |
| Checkout Abandonment | Abandonment of the checkout tunnel after completing at least one step. Distinct from cart abandonment, it signals specific friction in the finalization process. |
| Checkout Abandonment Rate | The percentage of sessions that initiated checkout without resulting in a confirmed order. A key indicator of checkout funnel performance. |
| Step Drop-off Rate | The exit rate at each checkout step, enabling precise identification of friction points within the funnel. |
| Form Completion Rate | The rate at which checkout forms are fully completed. A low rate signals friction in the fields being requested. |
| Order Confirmation Page | The page displayed after an order is placed, confirming the order number and summary details. Also known as the Thank You Page. |

---

## B. Payment, Transaction & Security

| Term | Definition |
|---|---|
| PSP | Payment Service Provider: a payment processing company (e.g. Adyen, Stripe, Mollie) that connects the merchant with banks and card networks. |
| Acquirer | A bank or financial institution that processes transactions on behalf of the merchant and transfers funds after deducting fees. |
| Issuer | The bank that issued the card used by the customer. The issuer is responsible for authorizing or declining the transaction. |
| Authorization | The step where the issuing bank verifies card validity and fund availability, then authorizes the transaction without yet debiting the account. |
| Authorization Rate | The percentage of transactions authorized out of all payment attempts. One of the most critical KPIs for checkout performance. |
| Capture | The triggering of actual settlement after authorization. Can be immediate (standard payment) or deferred (order prepared before debiting). |
| Soft Decline | A temporary transaction refusal by the issuing bank (insufficient funds, exceeded limit, 3DS required), which may be accepted after a retry or additional authentication. |
| Hard Decline | A permanent transaction refusal (stolen card, closed account, detected fraud). Any further retry attempt is futile. |
| Decline Rate | The rate of payment refusals across all submitted transactions. A high decline rate is a direct signal of revenue loss. |
| Retry Logic / Smart Retry | An automated mechanism that resubmits a transaction after a soft decline, adjusting parameters (timing, amount, routing) to maximize acceptance rate. |
| Payment Orchestration | A technology layer that dynamically routes transactions to the best-performing PSP based on defined rules (authorization rate, cost, payment method, geography). |
| 3DS / 3D Secure | A strong cardholder authentication protocol (via SMS code, biometrics, or in-app approval), mandatory under PSD2 in Europe. |
| Frictionless Authentication | A 3DS2 flow where authentication is validated transparently without customer interaction, through behavioral and risk data analysis. |
| SCA | Strong Customer Authentication: a regulatory requirement under PSD2 mandating customer identity verification via at least two factors (knowledge, possession, biometrics). |
| PSD2 | European Payment Services Directive requiring SCA and opening access to banking data via API (Open Banking). |
| Tokenization | The replacement of sensitive card data with an encrypted identifier (token), securing storage and transmission without exposing real information. |
| Network Tokenization | Tokenization performed directly at the card network level (Visa, Mastercard), delivering higher authorization rates and better card update management. |
| Vault | A secure storage system hosting customer payment tokens, enabling card data pre-fill without re-entry. |
| Wallet Payment | Payment via digital wallet (Apple Pay, Google Pay, PayPal) integrating pre-stored card and address data, significantly reducing checkout friction. |
| BNPL | Buy Now Pay Later: an installment or deferred payment option (e.g. Klarna, Alma) allowing customers to spread payments without using a credit card. |
| APM | Alternative Payment Methods: all payment methods outside traditional bank cards (bank transfers, wallets, BNPL, cryptocurrencies, etc.). |
| Split Payment | Payment for an order distributed across multiple payment methods (e.g. card combined with a gift voucher). |
| Multi-currency | The ability to accept and display transactions in multiple currencies, with conversion applied at the time of checkout. |
| Chargeback | A forced refund initiated by the issuing bank at the customer's request, reversing the transaction and penalizing the merchant with a fee. |
| Refund | A total or partial reimbursement of an order, initiated by the merchant. |
| Interchange Fee | A fee charged by the issuing bank on each transaction, passed on through the merchant's PSP costs. |
| Risk Engine | An automated analysis system that evaluates fraud risk on each transaction in real time. |
| Fraud Scoring | A risk score calculated for each transaction using behavioral, technical, and historical data, used to decide whether to accept, decline, or escalate. |
| PCI-DSS | An international payment data security standard imposing strict requirements on the storage, processing, and transmission of card information. |

---

## C. Performance, Conversion & CRO

| Term | Definition |
|---|---|
| Conversion Rate | The percentage of visitors who completed a purchase. Can be calculated globally (site-wide) or per funnel step (checkout conversion rate). |
| Checkout Conversion Rate | The rate of confirmed orders relative to the number of sessions that initiated checkout. A direct indicator of checkout funnel performance. |
| Payment Success Rate | The rate of transactions resulting in an accepted payment out of all payment attempts submitted. |
| Revenue Per Visitor (RPV) | The average revenue generated per unique visitor. Combines conversion rate and average order value to measure overall site performance. |
| AOV | Average Order Value: the average revenue generated per order. |
| GMV | Gross Merchandise Volume: the total gross value of merchandise sold over a period, before deducting returns and discounts. |
| Net Sales | Net revenue after deducting returns, cancellations, and discounts. |
| UPT | Units Per Transaction: the average number of items per order. |
| LTV / CLV | Lifetime Value / Customer Lifetime Value: the total economic value generated by a customer over the entire duration of their relationship with the brand. |
| CAC | Customer Acquisition Cost: the average cost of acquiring a new customer, including marketing and sales expenditures. |
| Cart Abandonment | Abandonment of the cart before entering checkout. Industry average rate: 70 to 80%. Signals friction around price, shipping costs, or trust. |
| Browse Abandonment | Abandonment after viewing a product page without adding to cart. Indicates a product conviction deficit. |
| Funnel | A representation of the conversion tunnel from first contact to purchase, used to identify drop-off stages. |
| A/B Test | A comparison of two versions of a page or component to identify which performs better on a given metric. |
| Multivariate Test | Simultaneous testing of multiple variables on the same page to identify the most effective combinations of elements. |
| Heatmap | A heat map visualizing the most clicked or hovered areas of a page, useful for optimizing visual hierarchy. |
| Session Replay | A recorded playback of a user session, enabling observation of real behavior and identification of friction points. |
| CTR | Click-Through Rate: the click rate on an element (button, link, banner). |
| Bounce Rate | The percentage of visitors who leave the site after viewing only one page. |
| Exit Rate | The exit rate on a given page, regardless of prior navigation depth. |
| KPI | Key Performance Indicator: a measurable metric used to evaluate the achievement of an objective. |
| LCP | Largest Contentful Paint: the loading time of the largest visible element on the page. A reference Web Vital for perceived performance. |
| CLS | Cumulative Layout Shift: visual instability of a page during loading. Impacts user experience and search engine ranking. |
| Web Vitals | A set of indicators defined by Google measuring the quality of user experience (LCP, CLS, INP). |
| Page Speed | The loading speed of a web page, a direct factor in both conversion rate and search engine ranking. |

---

## D. Pages & Navigation

| Term | Definition |
|---|---|
| HP | Home Page: the website's homepage, the first point of contact for the majority of visitors. |
| PLP | Product Listing Page: a page listing products by category, search query, or applied filters. |
| PDP | Product Detail Page: a detailed product page including description, images, price, variants, and an add-to-cart button. |
| SRP | Search Results Page: the page displaying results from an internal site search. |
| Landing Page | A dedicated page optimized to convert targeted traffic from an advertising campaign or email. |
| Quick View | A quick product preview displayed as an overlay, without leaving the current page. |
| Login Page | The page where customers sign in to their account. |
| My Account | The customer area for managing orders, personal data, saved payment methods, and returns. |
| Wishlist | A save list allowing customers to bookmark products for a future purchase. |
| Cross-sell | A suggestion of complementary products during checkout or on the product page (You may also like). |
| Upsell | A proposal of a higher-tier or premium version of a product during the purchase journey. |
| Error Page | An error page (404, 500) displayed when content is not found or a server failure occurs. |
| Store Locator | A tool for locating physical stores on an omnichannel e-commerce website. |

---

## E. Order, Logistics & Omnichannel

| Term | Definition |
|---|---|
| OMS | Order Management System: a system orchestrating the complete order lifecycle, from validation to delivery and returns. |
| WMS | Warehouse Management System: a system managing warehouse operations (receiving, storage, picking, shipping). |
| Fulfillment | The complete order processing workflow: picking, packing, shipping, and return management. |
| BOPIS / Click & Collect | Buy Online Pick-up In Store: purchasing online with in-store pickup. Reduces shipping costs and drives foot traffic to the point of sale. |
| BORIS | Buy Online Return In Store: the ability to return an online order in a physical store. |
| Ship from Store | A fulfillment model where orders are shipped from a physical store rather than a central warehouse, reducing delivery lead times. |
| Last Mile Delivery | The final delivery step, from the local depot to the end customer. The most costly and most visible stage for customer experience. |
| Carrier | A shipping provider responsible for delivering orders (Colissimo, Chronopost, DHL, UPS, etc.). |
| SLA | Service Level Agreement: a contractual commitment on service levels covering order processing times and quality standards. |
| Parcel Tracking | Real-time tracking of a parcel's transit, accessible to the customer via a tracking number. |
| RMA | Return Merchandise Authorization: the process of authorizing and managing product returns. |
| Cut-off Time | The order deadline for guaranteeing same-day dispatch. |
| Order Splitting | The automatic splitting of a single order into multiple shipments based on product availability or origin. |
| Stock Accuracy | The reliability of displayed stock levels compared to actual physical inventory. Poor stock accuracy leads to order cancellations. |

---

## F. Marketing, CRM & Customer Data

| Term | Definition |
|---|---|
| CRM | Customer Relationship Management: a system centralizing customer data to drive marketing, sales, and support actions. |
| CDP | Customer Data Platform: a platform unifying customer data from multiple sources (web, CRM, email, offline) into a single profile. |
| Marketing Automation | Automated sending of communications (emails, SMS, notifications) triggered by defined behaviors or events. |
| Triggered Email | An email sent automatically following a specific event (cart abandonment, first order, anniversary). |
| Email Deliverability | The ability of an email to reach the inbox without being filtered as spam. Depends on sending domain reputation and list quality. |
| Loyalty Program | A loyalty scheme rewarding repeat purchases with points or exclusive benefits. |
| Segmentation | Dividing a customer base into homogeneous groups based on behavioral, demographic, or transactional criteria. |
| Personalization | Adapting content, offers, or the browsing experience based on a visitor's profile or behavior. |
| Customer Journey | The full set of touchpoints between a customer and a brand, from first contact through to loyalty. |
| RFM | A customer scoring model based on Recency of purchase, Frequency of orders, and Monetary value spent. |
| First-party Data | Data collected directly by the brand through its own channels (website, app, CRM), without intermediaries. |
| Zero-party Data | Data voluntarily shared by the customer (preferences, purchase intentions), with high value in terms of consent and accuracy. |
| Attribution Model | A model defining how credit for a conversion is distributed across the marketing channels that contributed to the customer journey. |
| Churn | Churn rate: the percentage of customers lost over a given period. |
| Retention | The ability to keep customers active over time, measured by repurchase rate and purchase frequency. |
| Opt-in | Explicit customer consent to receive marketing communications. Mandatory under GDPR. |
| GDPR | General Data Protection Regulation: a European regulation governing the collection, storage, and use of personal data. |
| Push Notification | A notification sent to a user's browser or mobile app, even outside an active session. |

---

## G. Architecture & Integration

| Term | Definition |
|---|---|
| API | Application Programming Interface: a protocol allowing two systems to communicate and exchange data in a standardized way. |
| REST API | An API structured around HTTP verbs (GET, POST, PUT, DELETE), the dominant standard for e-commerce integrations. |
| Webhook | An automatic notification sent by one system to another in real time when an event occurs (payment confirmed, order shipped). |
| Headless Commerce | An e-commerce architecture that decouples the frontend (user interface) from the backend (business logic, data), connected via API. |
| Composable Commerce | An architectural approach assembling specialized best-of-breed technology components via API, as opposed to monolithic platforms. |
| MACH | An acronym for modern architecture principles: Microservices, API-first, Cloud-native, Headless. The reference standard for scalable e-commerce platforms. |
| SaaS | Software as a Service: a cloud-based software delivery model requiring no local installation. |
| CDN | Content Delivery Network: a geographically distributed server network that accelerates the loading of static content (images, scripts). |
| Feature Flag | A mechanism allowing a feature to be enabled or disabled in production without a deployment, used for gradual rollouts and rollbacks. |
| CI/CD | Continuous Integration / Continuous Deployment: development practices that automate testing and continuous deployment of updates. |
| Caching | Storing data or pages in cache to speed up response times and reduce server load. |
| Microservices | A software architecture that breaks an application into independent services, each responsible for a specific function. |
| Middleware | An intermediate software layer facilitating communication and data exchange between heterogeneous systems. |
| ETL | Extract, Transform, Load: the process of extracting, transforming, and loading data between systems. |

---

## H. Acquisition & Traffic

| Term | Definition |
|---|---|
| SEO | Search Engine Optimization: a set of techniques aimed at improving a website's organic ranking in search engine results. |
| SEA | Search Engine Advertising: paid advertising on search engines (Google Ads, Bing Ads), delivered through keyword-based bidding. |
| ROAS | Return On Ad Spend: advertising ROI calculated by dividing revenue generated by advertising spend. |
| CPC | Cost Per Click: the unit cost paid by the advertiser for each click on an ad. |
| CPA | Cost Per Acquisition: the average cost to generate a conversion (purchase, sign-up, lead). |
| CPM | Cost Per Mille: the cost per thousand ad impressions. A billing model focused on visibility rather than clicks. |
| Organic Traffic | Traffic generated through natural search engine ranking without direct advertising spend. |
| Paid Traffic | Traffic generated through paid advertising campaigns. |
| Audience Sync | Synchronization of CRM audiences to media platforms (Meta, Google, LinkedIn) for ad targeting. |
| Lookalike Audience | An algorithmically built audience designed to resemble a defined source audience (active customers, recent buyers). |
| Social Commerce | A purchase process initiated and completed directly within a social media platform. |