Informal. deltoid muscles.
Origin of delts
First recorded in 1965–70; by shortening
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for delts
Historical Examples of delts
They are not heavy, and besides, I am to walk only as far as Mrs. Delts.
The best tick I have is none too good for Mr. Gardiner, was Mrs. Delts reply, which left the young man speechless.