a principal | Principal; prime; chief; leading; of chief or pricipal importance. (defdate|from 15th c.)
a Principal or chief in size or extent; largest; consisting of the largest part; most important by reason or size or strength.
n (obsolete|except in might and main) strength|Strength; power; force; violent effort. (defdate|from 9th c.)
n That which is chief or principal; the chief or main portion; the gross; the bulk; the greater part.
n A large pipe or cable providing utility service to a building or area, such as water main or electric main. (defdate|from 17th c.)