To struggle with might and main. How to use main in a sentence. It signifies the central or principal focus, significance, or purpose of a subject or object. The most important fact in a situation: Most important or largest: The meaning of main is physical strength : The principal or most important part or point usually in the phrase in the main, mostly, chiefly Physical strength, power, or force: The chief or principal part or point: Chief or principal in rank, importance, size, etc 2. The main of their investments was lost during the war. [from 15th c. ] quotations the main office is actually one of the smaller rooms. · main (not comparable) of chief or leading importance; Sheer or utmost (esp in the phrase by main force) Force —used in the phrase with might and main. Main (meɪn) adj (prenominal) 1. A pipe that carries…. Find 561 different ways to say main, along with antonyms, related words, and example sentences at thesaurus. com. The main social event of the summer was a dance and reception. Main refers to the primary or most important aspect or part of something. The main thing is to keep calm and don’t get angry.