I am used to it from Linux terminals. Using both Terminal and iTerm.
Try ESC. instead, this will work in both Terminal and iTerm.
By default, the Alt-key doesn’t work in MacOS (OSX) Terminal. Simple solution for this problem:
Terminal > Preferences > Settings > Keyboard
Use option as meta key at the bottom!
This will disable Mac extended characters (ex. Option+g = © Copyright char), but no worry if you dont need them.