-aceous

1.
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
< Latin -āceus; see -ous
British Dictionary definitions for -aceous

-aceous

suffix
1.
relating to, belonging to, having the nature of, or resembling: herbaceous, larvaceous
Word Origin
New Latin, from Latin -āceus of a certain kind; related to -āc,-āx, adjectival suffix
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."

-aceous in Science
-aceous  
A suffix used to form adjectives meaning "made of" or "resembling" a particular substance or material, such as silicaceous, containing silicon.