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.

(astronomy) A major grouping of stars represented on a Hertzsprung-Russell diagram by a nearly uniform band of increasing luminosity with increasing surface temperature.

plural of Maine Coon

A large, fluffy semi-longhair domestic cat of a breed that originated in Maine.

plural of main road

The pipe through which water from an engine is delivered to an elevated reservoir.

(fox hunting) A fox's primary lair.

plural of main street

the principal street of a town, but not necessarily named "Main Street" (qv); there can be more than one main street in some towns.