---
title: Glossary
description: Definitions for terms used across API Shield documentation.
image: https://developers.cloudflare.com/core-services-preview.png
---

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# 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 identifier 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.                                                    |

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