The part made to be held, and the name a thing is reached by. Both are the graspable end of something larger.
Old English handlian (to touch, feel with the hands), from hand; both the graspable end of a physical thing and the name by which a person is reached.
Whatever is too large to hold whole gets a smaller part built for gripping, whether that part is a lever or a name — and the smaller part is what everyone actually reaches for.