cow
牛 centers on the animal cow, including cattle in general.
牛 is a pictograph of a cow's head with horns, simplified to the modern four-stroke form.
The two upward strokes are horns, and the horizontal and vertical strokes form the head and face: 牛 is a cow.
For ギュウ, imagine a cow mooing with a deep 'gyuuu' sound: gyuu -> ギュウ.
cattle (Bos taurus); cow; bull; ox; calf
(cow's) milk
beef
Wagyu (any of four breeds of Japanese cattle); Wagyu beef
great burdock (Arctium lappa); gobo
to control; to take the lead in; to have under one's thumb
snail
water buffalo (Bubalus bubalis); domestic Asian water buffalo
bullfighting; bullfight
sea slug (various orthogastropod species, esp. of order Nudibranchia); nudibranch
dairy cow; dairy cattle; milk cow; milch cow
cowhide; oxhide
cow shed; cattle barn
calf
snail's pace; slow progress
cattle manure; cow dung; cowpat; bullshit
beef tallow
cow; heifer
mad cow disease; bovine spongiform encephalopathy; BSE
American bullfrog (Lithobates catesbeianus)