What's the font in Mac OS X's GUI? What is the font that's used in Mac OS X's graphical user interface (GUI), in the menus, dialog boxes, etc.? Is it different from what was used in the classic Mac OS (i.e. OS 9 or older)? If so, what are the fonts back then? I like the font but never knew what it was. Thanks.
The font you see in most places on Mac OS X is Lucida Grande, it is the system font in OS X 10.1 Puma to 10.9 Mavericks. Mac OS 1-7 used Chicago, then Mac OS 8 and 9 used Charcoal.

The most recent additions are Helvetica Neue (OS X 10.10 Yosemite) and San Francisco (OS X 10.11 El Capitan through Mojave)