-oid Also -oidea and -oidal.
[Greek -oeidēs; related to eidos, form.]
Words in this ending are adjectives and nouns that indicate a form or resemblance, sometimes an imperfect or incomplete one. A few members from a large group: android (Greek anēr, andr-, man), an artificial biological lifeform with a human appearance; cardioid (Greek kardia, heart), in the shape of a heart, especially a heart-shaped curve; dendroid (Greek dendron, tree), tree-shaped or branching; factoid, either something that is reported and repeated so often that it becomes accepted as fact, or a brief or trivial item of news or information; meteoroid, a small body moving in the solar system that would become a meteor if it entered the earth's atmosphere.
The ending can also indicate an animal that is a member of a systematic taxonomic grouping that ends in -oidea, usually a superfamily, a category that ranks above the family and below the order: a salmonoid is a fish of the superfamily Salmonoidea that includes the salmon; a hominoid (Latin homo, homin-, human being) is a primate of the superfamily Hominoidea that includes humans, their fossil ancestors, and the great apes; scarabaeoid is a beetle of a large group, the Scarabaeoidea, that includes the scarab and stag beetles.
Adjectives are formed with -oidal (see -al1): cuboidal, of the nature of an cuboid, a roughly cube-shaped figure; adenoidal, relating to the adenoids (Greek adēn, gland), a structure between the back of the nose and the throat.
See also -ploid.