cavity, hole, slit, very, great, exceedingly
孔 centers on an opening or empty space: a cavity, hole, or slit. The senses "very," "great," and "exceedingly" are less common and likely arise from the idea of a hole being deep or extreme.
孔 combines 子 (child) with 乚, which may represent a hole or opening. The exact historical development is uncertain, but the character likely depicts a child emerging from or passing through an opening.
A child 子 beside a curved hook 乚 that looks like a hole: imagine a child peeking through a cavity or slit.
For コウ, picture a child shouting "coo!" through a hole: coo -> コウ, and the sound echoes in the cavity.
Confucius
peafowl (incl. the male peacock, female peahen, and young peachick)
pupil (of the eye)
perforation; punching; boring; drilling
porous; open (weave)
nostril; naris
pore; stoma; stigma; vesicle
Indian peafowl (Pavo cristatus); common peafowl; blue peafowl
card punch
card punch
spot punch
tape punch
tape punch
Ya Boy Kongming! (manga series)
Adiantum edgeworthii (species of maidenhair fern)
manhole
index hole
inner hole
monotremes; Monotremata
foramen ovale; oval foramen of the fetal heart