a suffix with the meanings “resembling, having the nature of,” “made of,” occurring in loanwords from Latin (cretaceous; herbaceous) and forming adjectives in English on the Latin model (ceraceous), especially adjectival correspondents to taxonomic names ending in -acea and -aceae: rosaceous.
Origin of -aceous
< Latin -āceus; see -ous
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for -aceous
suffix forming adjectives
relating to, belonging to, having the nature of, or resemblingherbaceous; larvaceous
Word Origin for -aceous
New Latin, from Latin -āceus of a certain kind; related to -āc, -āx, adjectival suffix
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
Word Origin and History for -aceous
word-forming element denoting "belonging to, of the nature of," from Latin -aceus, enlarged form of adjectival suffix -ax (genitive -acis); see -acea. Especially in biology, "pertaining to X order of plants or animals."
Online Etymology Dictionary, © 2010 Douglas Harper
Science definitions for -aceous
A suffix used to form adjectives meaning made of or resembling a particular substance or material, such as silicaceous, containing silicon.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.