Let's Compare Mucosa and Serosa. 1  MUCOSA VS.  Mucosa. The mucous membranes (or mucosae or mucosas; singular mucosa) are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. mucosa \mucosa\ n.
Definition of dropper for English Language Learners. : a glass or plastic tube that is used to measure out liquids by drops.
droplet - a tiny drop. drib, driblet, drop - a small indefinite quantity (especially of a liquid); he had a drop too much to drink; a drop of each sample was analyzed; there is not a drop of pity in that man; years afterward, they would pay the blood-money, driblet by driblet--Kipling.