longitudinal

Short definition from Wiktionary

Adjective

1. 1
   Relating to length.
2. 2
   Relating to the geographical longitude.
3. 3
   Running in the direction of the long axis of a body.
4. 4
   Forward and/or backward, relative to some defined direction.
5. 5
   Sampling data over time rather than merely once.

Noun

1. 1
   Any longitudinal piece, as in shipbuilding etc.
2. 2
   A railway sleeper lying parallel with the rail.