Cereinae is a subtribe of cacti in the tribe Cereeae, subfamily Cactoideae. It is one of the three subtribes into which the tribe Cereeae is divided, the others being Rebutiinae and Trichocereinae.

Cereus ( "serious") is a genus of cacti including around 33 species of large columnar cacti from South America. The name is derived from Greek (κηρός) and Latin words meaning "wax", "torch" or "candle". Cereus was one of the first cactus genera to be described; the circumscription varies depending on the authority. The term "cereus" is also sometimes used for a ceroid cactus, any cactus with a very elongated body, including columnar growth cacti and epiphytic cacti.