also check-out, 1944, from the verbal phrase; see check (v.1) + out (adv.). Originally "training given to a pilot for using a specific aircraft;" hotel sense "administrative procedure followed when guests leave after a stay" is from 1958. Retail sense "place where one pays for goods selected" is from 1947.
the checkout here is 12 noon
checker-board
checkered
checkers
check-list
checkmate
checkout
checkpoint
check-up
cheddar
cheek
cheeks