10 letters · 18 points in Scrabble
noun a small elevator used to convey food (or other goods) from one floor of a building to another
originFrom dumb (“unable to speak”) + waiter, originally separate words and describing the portable table's inability to relate gossip after the meal. By the use of the term to describe small service elevators in American homes in the 1840s, it simply meant dumb as “mechanical”, “unable to speak at all”.
Etymology from Wiktionary, CC BY-SA 3.0