The principal place in which a company does business.

(UK, finance) The principal stock market of the London Stock Exchange.

plural of main market

(grammar) A clause that can stand alone syntactically as a complete sentence and contains at least a subject and a verb.

(grammar) The verb in a clause with the highest semantic content.

The conduit through which coal gas or natural gas is conveyed to users.

plural of gas main

(chemistry) In the periodic table of the elements, any of the eight groups (columns) of elements that contain the lightest (and most common) elements.

The principal pipe, usually underground, for conveying water to residential and business properties.

(linear algebra) The entries of a square matrix from the top left to the bottom right.