n. pl. lav·a·to·ries
1. A room equipped with washing and often toilet facilities; a bathroom.
2. A washbowl or basin, especially one permanently installed with running water.
3. A flush toilet.
[Middle English, piscina, from Late Latin lavātōrium, from lavātor, launderer, from Latin lavāre, to wash; see leu(ə)- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.