faucet - Probably comes from French fausset, meaning "bore, tap." More...

tattoo - In the military sense—of a signal summoning soldiers to their quarters at night—it was originally written tap-too, from a Dutch word taptoe, meaning "close the tap" (of a cask), which was told to soldiers when they were expected to return to their quarters. More...

tick, tickle - Tick, as in "sound of a clock," "mark of correctness," originally meant "light touch, tap," and its modern senses are recent developments; tickle is probably a derivative of this version of tick. More...

tit for tat - Probably borrowed from Dutch tip for tap, "blow for blow." More...