A dewdrop is a single small drop of dew — one little ball of that night water, often hanging from the tip of a leaf or sitting on a blade of grass. Dew is the water in general; a dewdrop is one drop you could almost count. It is a gentle, slightly pretty word, common in nature writing and in talk with children, but adults use it too when they are looking closely. Though actually people sometimes call any small drop a dewdrop; strictly it is dew, not rain or tears. In the sun a dewdrop can flash like a tiny light, which is why the word turns up in poems.