If your app makes access requests to the Zoom API, then your app is considered the Client.

Client - The application that requests access to the user's information.

If your app is integrating with the Zoom API to obtain user-related information, then the Zoom API server is considered the resource server. Resource Server - The server that hosts the resource.Resource Owner - A user in a Zoom account who can either authorize or decline a Client from accessing information related to the user's Zoom account.These roles are actively involved in the process of authentication with Zoom APIs: The OAuth protocol defines four specific roles. To begin using the OAuth protocol for your app's authentication with Zoom, you must create either an OAuth app or a Server-to-Server OAuth app in the Zoom App Marketplace. The following sections provide an overview on the OAuth protocol. OAuth 2.0 lets applications obtain access to Zoom resources, such as the user's profile information, via the Zoom API. Zoom must authenticate each HTTP request made to the Zoom API. Understanding Personal Meeting ID (PMI).Both of these terms refer to an app integrating with the Zoom API. Note: In this document, you will see the terms client and app used interchangeably.

Zoom info 2.0