Why was "tantrum" trending last week?
1700, "distiller," agent noun from drop (v.). Meaning "small tube from which liquid may be made to fall in drops" is from 1889.
dropper drop·per (drŏp'ər)n. A device that produces drops, especially a small tube with a suction bulb at one end for drawing in a liquid and releasing it in drops. Also called instillator.