1.AdjectivePertaining to the zoologic infraorder Cetacea, or associated with species falling under that taxonomic hierarchy.
"The poached blubber was definitely cetacean in origin, but the particular species could not be identified."
2.AdjectiveResembling or relating to large aquatic mammals.
"The obese woman, ungainly on land, moved with a kind of cetacean grace in the water."
3.NounA marine mammal belonging to the infraorder Cetacea, including dolphins, porpoises, and whales, characterized by a streamlined body, one or two blowholes, tail flukes, and fin-like forelimbs without hind limbs.
"The tour promised spiritual experiences with humpback whales and other cetaceans, but all we saw were seagulls and a dead sea otter."