What is "regiment of the line"

Regiment \Reg"i*ment\ (-ment), n. [F. r['e]giment a regiment of men, OF. also government, L. regimentum government, fr. regere to guide, rule. See Regimen.]

1. Government; mode of ruling; rule; authority; regimen. [Obs.]
   --Spenser. ``Regiment of health.''
   --Bacon.

   But what are kings, when regiment is gone, But perfect shadows in a sunshine day?
   --Marlowe.

   The law of nature doth now require of necessity some kind of regiment.
   --Hocker.

2. A region or district governed. [Obs.]
   --Spenser.

3. (Mil.) A body of men, either horse, foot, or artillery, commanded by a colonel, and consisting of a number of companies, usually ten.

   Note: In the British army all the artillery are included in one regiment, which (reversing the usual practice) is divided into brigades.

   Regiment of the line (Mil.), a regiment organized for general service; -- in distinction from those (as the Life Guards) whose duties are usually special. [Eng.]