by a margin (of something)
by a margin (of something)
By a particular amount of something, especially points in a game or contest, over or below another amount. 17–1? Wow, I can't believe they won by such a large margin. Don't get cocky—you guys only won by a margin of three points.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.