a combining form meaning “other,” used in the formation of compound words (allotrope) and in chemistry to denote the more stable of two geometric isomers.
Also (except in chemistry) especially before a vowel, all-.

Origin of allo-

< Greek, combining form of állos other; cognate with Latin alius, else Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for allo-


before a vowel all-

combining form

indicating difference, variation, or oppositionallopathy; allomorph; allophone; allonym

Word Origin for allo-

from Greek allos other, different
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for allo-



Other; different:allotransplantation.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.