4to, Often written: 4° a book size resulting from folding a sheet of paper, usually crown or demy, into four leaves or eight pages, each one quarter the size of the sheet
2.
(formerly) a size of cut paper 10 in. by 8 in. (25.4 cm by 20.3 cm)
a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.
a chattering or flighty, light-headed person.
a fool or simpleton; ninny.
a scrap or morsel of food left at a meal.
a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.