sirenian vs sea cow

sirenian and sea cow both are nouns.

Word	Noun	Adjective	Verb	Adverb
sirenian	Yes	No	No	No
sea cow	Yes	No	No	No

As nouns, sirenian and sea cow are synonyms defined as:

sirenian and sea cow: any of two families of large herbivorous aquatic mammals with paddle-shaped tails and flipper-like forelimbs and no hind limbs

Other synonyms of sirenian include sirenian mammal.

sirenian (noun)	sea cow (noun)
any of two families of large herbivorous aquatic mammals with paddle-shaped tails and flipper-like forelimbs and no hind limbs	any of two families of large herbivorous aquatic mammals with paddle-shaped tails and flipper-like forelimbs and no hind limbs