[emacs] How to set the font size in Emacs?

Aquamacs:

(set-face-attribute 'default nil :font "Monaco-16" )

From the Emacs Wiki Globally Change the Default Font, it says you can use either of these:

(set-face-attribute 'default nil :font FONT )

(set-frame-font FONT nil t)

Where FONT is something like "Monaco-16", e.g.:

(set-face-attribute 'default nil :font "Monaco-16" )

There was an extra closing parenthesis in the first suggestion on the wiki, which caused an error on startup. I finally noticed the extra closing parenthesis, and I subsequently corrected the suggestion on the wiki. Then both of the suggestions worked for me.