What is meaning of delt?

Answer 1

Dealt is the past tense of to deal.
Delta is the 4th letter of the Greek alphabet or the triangular plain at the mouth of a river that resembles the letter delta.
Delt has no meaning in English.

Answer 2

Delt typically refers to the triangular muscle that covers the shoulder joint, known as the deltoid muscle. It is responsible for lifting and rotating the arm. It is a common abbreviation used in fitness and anatomy discussions.