11 letters · 25 points in Scrabble
noun a transparent lubricating mucous membrane that covers the eyeball and the under surface of the eyelid
originFrom 1540s late Middle English, borrowing from Medieval Latin conjūnctīva (“serving to connect, connective”, feminine), ellipsis of membrāna conjūnctīva (“conjunctive membrane”).
Etymology from Wiktionary, CC BY-SA 3.0