some point or period in time

a day assigned to a particular purpose or observance

the recurring hours when you are not sleeping (especially those when you are working)

an era of existence or influence

United States writer best known for his autobiographical works (1874-1935)

a period of opportunity

the time for one complete rotation of the earth relative to a particular star, about 4 minutes shorter than a mean solar day

the period of time taken by a particular planet (e.g. Mars) to make a complete rotation on its axis