big time (plural big times)

1. The highest, or most prestigious level in any field, especially in entertainment.

   Synonyms: big league, major league

   • 2012, Ben Smith, Leeds United 2-1 Everton‎:

     This was a rare whiff of the big-time for a club whose staple diet became top-flight football for so long - the glamour was in short supply, however. Thousands of empty seats and the driving Yorkshire rain saw to that.

big time

1. (informal) By a large margin; with great significance.