-e·us \_ēəs\noun combining form (plural-ei \_ēˌī\ ; also-euses) Etymology: New Latin, from Latin, adjective suffix, composed of, of the nature of, or resembling (a specified substance) — more at -eous : muscle that constitutes, has the form of, or joins a (specified) part, thing, or structures < gluteus > < rhomboideus > < iliococcygeus >