noun
fur seal; northern fur seal
Rare standalone abbreviation of 膃肭臍 (おっとせい). Refers specifically to the northern fur seal (Callorhinus ursinus). Almost never used independently in modern Japanese; encountered mainly in historical or zoological contexts.
See also: 膃肭臍
「膃肭」は「おっとせい」の略称として使われることがあるが、現代ではほとんど見かけない。
膃肭 is sometimes used as an abbreviation for おっとせい, but it is rarely seen today.