-aceous

adjective suffix

1

a

: characterized by : full of

setaceous

b

: consisting of

diatomaceous

: having the nature or form of

tuffaceous

2

a

: of or relating to a group of animals typified by (such) a form

cetaceous

or characterized by (such) a feature

crustaceous

b

: of or relating to a plant family

solanaceous

Word History

Etymology

borrowed from Latin -āceus "having the nature of," extended form of -eus, going back to *ei̯os

Note: Latin -āceus is an extension of the suffix -eus, meaning "being made of, consisting of," usually applied to a noun designating a material (aureus, argenteus, etc.). Earlier attested derivatives, from Cato and Varro, are from names of plants or plant-based substances (hederāceus, cf. hedera "ivy"; mustāceus/mustāceum "cake made with must (mustum) and ivy leaves"; vīnāceus "refuse from wine pressing"; bētāceus, cf. bēta "beet"; farrāceus, cf. farr, farris "emmer"; lolleāceus, cf. lolium "darnel"). Contrasting with these are the jocular formations gallīnāceus ("of poultry"; cf. gallīna "hen") and Gēryonāceus (cf. Gēryōn, a mythical monster) in Plautus. The origin of the -āc- formative is uncertain. It has been suggested that the basis was re-segmentation of a hypothetical *portulāceus, from portulāca, "purslane"—something of a stretch, though it does point to the possible relevance of -ācus or -āca as a suffix itself.

Kids Definition

-aceous

adjective suffix

-a·​ceous

ˈā-shəs

: consisting of

carbonaceous

: having the nature or form of

herbaceous

Etymology

from Latin -aceus "consisting of"