mouth
口 centers on the mouth as an opening: the physical mouth, and by extension any opening or entrance that resembles one.
口 is a pictograph of an open mouth. The modern square form preserves the simple outline.
The square shape looks like an open mouth. Picture a wide-open mouth saying 'ahh'.
For コウ, imagine a mouth opening wide to say 'ko' as in 'koala': ko -> コウ, and the mouth shape matches the square.
mouth
population
account (e.g. bank)
exit; way out
entrance; entry; gate; approach; mouth
counter; window; teller window; ticket window
(verbal) abuse; speaking ill of people; bad-mouthing; name-calling; slander; abusive language; insulting remarks
(verbal) abuse; name-calling; abusive language; insulting remarks
mouth of river; estuary
tone (of voice); manner of talking
modus operandi; criminal technique; trick
aperture; bore; calibre; caliber
word of mouth
pet saying; favorite phrase; stock phrase; catchphrase
west entrance; west exit
east entrance; east exit
excuse; pretext
big mouth; mouth opened wide
taciturn; reticent; quiet; silent; untalkative
quarrel; argument; row; (verbal) dispute
lipstick
meddling (in); butting in; interference; poking one's nose into
north entrance; north exit
oral; verbal; spoken; parol
south entrance; south exit
opening; aperture (e.g. camera)
mouthful; morsel; bite
dry taste (e.g. sake, wine)
fast-talking; rapid talking
faucet; tap
(opening of a) wound; cut
clever; intelligent; bright; smart; wise; sensible; shrewd
cut end; section; opening; slit
burner; nozzle; origin of a fire
lip service; mere words; professions
whistle (sound made with the lips)
number of words a person speaks
exit and entrance
backdoor; rear entrance; rear exit
malicious gossip; backbiting; speaking ill behind someone's back
cut end; edge (of a page, etc.)
beginning; start; first step
frontage; width (of a building, plot of land, etc.)
spout
vocal message; speech; statement
quarrel; dispute; argument
forbidding mentioning (something to others); imposing silence (on); ordering (someone) to keep quiet; muzzling (someone); gagging; hushing up
way of reciting; way of telling a story
mediation; good offices; intervention; mediator; middleman
spoken language; colloquial speech
door; doorway
to blurt out; to let slip; to say inadvertently; to come out with (e.g. nonsense)
to be stumped; to be at a loss; to be at one's wits' end; to be nonplussed
emergency exit
top of a waterfall
every person; every mouth
way of speaking
dictation; verbal statement
retort; back talk; backchat
fuse; pilot light
beginning of autumn; beginning of fall
to hesitate to say; to mumble; to hem and haw; to falter
position; job; employment; opening
technique; techniques
each and every person (saying); one and all; unanimously; in unison; separately; individually
account number (bank, etc.)
oral proceedings; oral pleadings
ticket barrier; ticket gate; wicket
(saying) with one voice; unanimously; in chorus; in unison; as one