SARAH: A nymph is the name for a supernatural spirit from classical mythology. Nymphs were usually depicted as young maidens inhabiting rivers, oceans, mountains or forests.

RALPH: In Shakespeare's time the word was beginning to be used poetically for any young woman, but it was also used euphemistically or humorously for a prostitute.

SARAH: Although it's unlikely Hamlet meant it in this latter sense; in any case, Ophelia certainly doesn't seem to take offense at the word.