In context|military|lang=en terms the difference between cavalry and line
is that
cavalry is (military) an individual unit of the cavalry arm of service while
line is (military) the regular infantry of an army, as distinguished from militia, guards, volunteer corps, cavalry, artillery etc.
As nouns the difference between cavalry and line
is that
cavalry is (military) the military arm of service that fights while riding horses while
line is a path through two or more points (
compare ‘segment’ ); a continuous mark, including as made by a pen; any path, curved or straight or
line can be (obsolete) flax; linen, particularly the longer fiber of flax.
As a verb line is
to place (objects) into a line (usually used with "up"); to form into a line; to align or
line can be (transitive) to cover the inner surface of (something), originally especially with linen or
line can be to copulate with, to impregnate.