means To make physical contact with something, usually by hand, or to affect someone emotionally — and a whole sprawl of senses in between, from a small amount to a delicate skill.

from From Old English, but really arriving through Old French 'tochier,' meaning to touch or strike. The deeper root is thought to be imitative — a Vulgar Latin 'toccare,' possibly echoing the sound of a knock or tap, the way 'tap' and 'tick' mimic their own little impacts. So the word may literally be the noise of contact made into a verb.