na-adjective, noun which may take the genitive case particle 'no', noun
Refers to living a long time; used as a noun or adjectivally (な-adjective, の-adjective). Often appears in wishes for health and long life.
祖父は長命で、百歳まで生きた。
My grandfather had a long life and lived to be 100.
長命の秘訣は何ですか。
What is the secret to a long life?