---
title: Glossary · Cloudflare API Shield docs
description: Review the definitions for terms used across Cloudflare's API Shield documentation.
source_url:
  html: https://angela-ssl-tls-updates.preview.developers.cloudflare.com/api-shield/glossary/index.md
  md: https://angela-ssl-tls-updates.preview.developers.cloudflare.com/api-shield/glossary/
---

Review the definitions for terms used across Cloudflare's API Shield documentation.

| Term | Definition |
| - | - |
| API call | Also known as an API request. An API call is a message sent to a server asking an API to provide a service or information. |
| API endpoint | The API endpoint is the location where API calls or requests are fulfilled. API Shield defines endpoints as a host, method, and path tuple. |
| API schema | The API schema defines which API requests are valid based on several request properties like target endpoint, path or query variable format, and HTTP method. |
| session identifier | A session identifier is a unique number that a website assigns to identify a specific user for the duration of their visit. |
| source endpoint | The source endpoint is the endpoint managed by API Shield in Endpoint Management by its routing feature. |
| target endpoint | The target endpoint is the ultimate destination that a request is sent to by API Shield's routing feature. |
