God's will; heaven's decree; mandate of Heaven; fate; destiny
Refers to a divine or cosmic plan, often in a philosophical or religious context. Can be used for both Western 'God's will' and East Asian concepts like the Mandate of Heaven.
He believed in his destiny.
Live according to heaven's will.
one's life; one's lifespan
A somewhat literary or old-fashioned way to refer to the length or course of a person's life, often with a nuance of fate or divine allotment.
Fulfill one's natural lifespan.
天命 frames one's fate as a mission or mandate given by heaven, whereas 運命 is a more neutral, general word for destiny.
天命 carries a religious or heaven-ordained nuance, while 命運 is used more secularly for the fate of a group or situation at a decisive juncture.
天命 suggests a mission determined by fate or heaven, whereas 使命 can be self-felt or assigned by any authority, not necessarily fate.
天寿 refers specifically to the natural length of a person's life, while 天命 refers to one's heaven-decreed fate, mission, or destiny, not necessarily lifespan.
From Chinese 天命 (tiānmìng), meaning 'Mandate of Heaven'. The Japanese reading is on'yomi. The word has been used in Japanese since classical times with both the religious/philosophical sense and the extended meaning of one's allotted lifespan.