1. The marine mammalia, including the whale, narwhal, porpoise, dolphin,&c.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• anthocerotacea,
• cactaceas,
• cebidea,
• xetacea,
• vetacea,
• fetacea,
• detacea,
• cwtacea,
• cstacea,
• cetace,
• cettacea,
• cetasea,
• cetacee,
• cetaceam,
• cettacean,
• cetacean,
• cletraceae,
• cyperacea,
• gnetacae,
• gnetacee

The adjective form of the word "cetacea" is "cetacean".

The plural form of the word "cetacea" is "cetaceans"

The singular form of the word "cetacea" is "cetacean"