Your Lightroom License is;
a. Cross platform Mac and / or Windows
b. You can have two active installations, with the proviso that only one is in use at any point in time.
c. The license is single owner / user.
d. You can install and uninstall as many time you deem necessary once you you adhere to the above.
e. There is no deactivate process like other Adobe Photoshop products, you just use the license key to activate. Same is available through a Creative Cloud Photographers package.
f. Your student and teacher license has the same privileges as the normal version, you have just purchased at a discounted price.
Keep your License key secure and available for upgrades and re installation. You should also register your product in your Adobe account in the event you have a need to retrieve it in the future.