What does "regiment" mean?

Additional senses

1. 2.(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.]
2. 3.To form into a regiment or into regiments. Washington.