under one's belt

under (one's) belt

1. In one's scope of experience. Once you get a few more major league games under your belt, you'll feel more comfortable.
2. Ingested or consumed. He should be less cranky after he gets some food under his belt.
See also: belt
Farlex Dictionary of Idioms.

under one's belt

Experienced or achieved, as in Once a medical student has anatomy under her belt, she'll have much less to memorize. This metaphoric expression likens food that has been consumed to an experience that has been digested. [Colloquial; first half of 1800s]
See also: belt
The American Heritage® Dictionary of Idioms by Christine Ammer.

under one's belt

A successful past experience. The term alludes to food that has been consumed, likening it to experience that has been digested. P. G. Wodehouse used it figuratively (Encounter, 1954): “Just as you have got Hamlet and Macbeth under your belt.”
See also: belt
The Dictionary of Clichés by Christine Ammer
See also:
  • under (one's) belt
  • under belt
  • under your belt
  • (one's) day in court
  • be in a world of (one's) own
  • be, live, etc. in a world of your own
  • get into a world of (one's) own
  • in (one's) own (little) world
  • in one's own world
  • live in a world of (one's) own