longitudinal vs perpendicular

longitudinal

adj
  • Forward and/or backward, relative to some defined direction. 

  • Relating to length, or to longitude. 

  • Running in the direction of the long axis of a body. 

  • Sampling data over time rather than merely once. 

noun
  • Any longitudinal piece, as in shipbuilding etc. 

  • A railway sleeper lying parallel with the rail. 

perpendicular

adj
  • at or forming a right angle (to something). 

  • Exactly upright; extending in a straight line toward the centre of the earth, etc. 

  • Independent of or irrelevant to each other; orthogonal. 

noun
  • A line or plane that is perpendicular to another. 

  • A device such as a plumb line that is used in making or marking a perpendicular line. 

How often have the words longitudinal and perpendicular occurred in a corpus of books? (source: Google Ngram Viewer )