noun
each person; each mouth; one after another
Usually used as 口々に, describing many people saying something separately, in turn, or all voicing their own words.
See also: 口々に
皆が口々にお礼を言った。
Everyone expressed their thanks one after another.
観客は口々にその演技をほめた。
The audience members praised the performance one after another.
noun
each entrance; every opening
A much less common literal extension of 口 meaning an entrance or opening; in modern everyday Japanese, 各入口 or 入口ごと is usually clearer.
古い記述で「城の口々を固める」とあれば、城の各入口を守るという意味になる。
If an old account says 'secure the kuchiguchi of the castle,' it means guarding each entrance of the castle.