知命 is read as ちめい (chimei) and means age 50.
ちめい
chimei
ちてきせいめい
intelligent life
ごじゅうちめい
at age fifty, one comes to know the will of Heaven
ちてきせいめいたい
しりあう
to get to know each other
しりあい
acquaintance
ちしき
knowledge
ちせい
intelligence
ちのう
ちかく
perception
しらんかお
unconcerned air
ちしきじん
intellectual
ちのうしすう
intelligence quotient