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
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.
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.
The audience each said, in their own words, that they were moved.
The residents each voiced their complaints one after another.
The children each shouted "Teacher!" at once.