Longitudinal /(?)/

Lon·gi·tu·di·nal

Longitudinal

a.
  1. Of or pertaining to longitude or length; as, longitudinal distance.
  2. Extending in length; in the direction of the length; running lengthwise, as distinguished from transverse; as, the longitudinal diameter of a body.

Longitudinal

n.
  1. A railway sleeper lying parallel with the rail.