Install on MORE THAN 2.You can install your app(s) on two or more computers.
Activate on up to 2.You can activate and remain signed in to the app(s) on up to two computers.
Use on 1.You can use your app on only one computer at a time.

Detailed description:

https://helpx.adobe.com/download-install/using/install-apps-number-of-computers.html