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.
Rating Newest Oldest. Best Answer: The United States Pharmacopeia defines the official dropper as one which delivers drops weighing between 45mg to 55mg. Assuming a density of 1 g/mL thus one drop should have a volume of 0.045 to 0.055mL, with an average of 0.05mL.