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.
a person or thing that drops. 2. a glass tube with a hollow rubber bulb at one end and a small opening at the other, for drawing in a liquid and expelling it in drops; medicine dropper. 3. a short-haired dog that is a cross between a pointer and a setter. Origin of dropper.