Meaning

noun a room or building equipped with one or more toilets

noun a bathroom sink that is permanently installed and connected to a water supply and drainpipe; where you can wash your hands and face

noun a toilet that is cleaned of waste by the flow of water through it

originFrom Middle English lavatorie, from Late Latin lavātōrium, from Latin lavāre (“to wash”) + -ium (forming places related to an activity). As a place to pan gold, via Spanish lavadero. Doublet of lavatorium and laver. See also lave.

Etymology from Wiktionary, CC BY-SA 3.0