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

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

(computing) The primary volatile memory of a computer, not including memory cache, persistent disk storage, or external storage.

plural of main line

Alternative spelling of mainline

Used other than figuratively or idiomatically: see main, drag. / (informal) The main street of a town or suburb, or the principal highway passing through a rural area.

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

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

Alternative form of main sequence.

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