かいぎゅう 海牛 LinksSentence search for 海牛Sentence search for かいぎゅうSentence search for カイギュウKanji details for 海 and 牛Edit in JMdict Noun1. sirenian (any aquatic mammal of order Sirenia, incl. manatees, and dugongs); sea cowUsually written using kana aloneOther formsカイギュウ Discussions Log in to talk about this word.