Long period at the top of eg show business

Wikipedia Word definitions in Wikipedia
Big Time or The Big Time may refer to:

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
"upper reaches of a profession or pursuit," c.1910 from vaudeville slang; the phrase was common in colloquial use late 19c.-early 20c. in a broad range of senses: "party, shindig, fun, frolic."

WordNet Word definitions in WordNet
n. the highest level of an occupation (especially in entertainment)

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
I. noun EXAMPLES FROM CORPUS ▪ I know he talked to her about what it was like before Jett hit the big time . ▪ It has taken him just five and a half years to make his mark in the big time . ▪ Lennie knows he hasn't any time to play with if Boro are to stay ...