The Alt key is known as the Option key on Macs. The Option key lets you perform shortcuts, type non-English letter accents, ...

(ALT GRaph key) A key on many international computer keyboards that is located where the right Alt key is normally found (right of the spacebar). When pressed along with a keyboard key, it enables ...

Microsoft wants you to use Alt+Space to open Copilot anytime on Windows 11 but you can disable it in the app settings.