-aceous

-aceous

or -acean
suff.
1.
a. Of or relating to: amylaceous.
b. Resembling or having the nature of: amentaceous.
2. Belonging to a taxonomic group: orchidaceous.

[From Latin -āceus.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

-aceous

suffix forming adjectives
relating to, belonging to, having the nature of, or resembling: herbaceous; larvaceous.
[New Latin, from Latin -āceus of a certain kind; related to -āc, -āx, adjectival suffix]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

-aceous

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, esp. adjectival correspondents to taxonomic names ending in -acea and -aceae: rosaceous.
[< Latin -āceus; see -ous]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.

-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® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.