-aceous, -acea, -aceae, -aceaen, -aceus
(Latin: a suffix; having the quality of, of the nature of, characterized by, belonging to, resembling)
There are hunderds of words that utilize the -aceous suffix which are not shown here; however, the following will present important examples.
A suffix that forms adjectives and is used with technical combinations, especially in biological terms: "pertaining or belonging to, of the nature of, or characterized by; to be full of, to possess abundantly". The suffix -acea usually denotes "orders and classes in zoology" while the suffix -aceae usually denotes "orders and families in botany" and -aceaen is used to denote members of "orders of the animal kingdom".
Also see this closely related -eous suffix unit.