coattail

coat +‎ tail

coattail (plural coattails)

1. The flap at the back of a coat that hangs down, sometimes below the waist.
   • 1892, Walter Besant, chapter II, in The Ivory Gate: A Novel, New York, N.Y.: Harper & Brothers, […], OCLC 16832619:

     At twilight in the summer […] the mice come out. They […] eat the luncheon crumbs. Mr. Checkly, for instance, always brought his dinner in a paper parcel in his coat-tail pocket, and ate it when so disposed, sprinkling crumbs lavishly […] on the floor.

2. (usually in the plural, figuratively) Success of a figure, organization or movement that transfers to those who associate with it.
   • 2012, The Economist, Oct 6th 2012; The Senate: Not so flippable:

     Mr Obama’s coat-tails may help lift Wall-Street-basher Elizabeth Warren past pickup-driving Everyman and one-time nude pin-up Scott Brown in Massachusetts […].

• tail

• on the coattails of
• ride the coattails

• tailcoat