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.
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British Dictionary definitions for -aceous
relating to, belonging to, having the nature of, or resembling: herbaceous; larvaceous
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
Scientific 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.