Gridiron /(?)/

Grid·i·ron

Gridiron

n.
  1. A grated iron utensil for broiling flesh and fish over coals.
  2. An openwork frame on which vessels are placed for examination, cleaning, and repairs. (Naut.)
  3. A football field; -- so called because of the resemblance of the parallel marked yard lines to a gridiron{1}. (Sport)

Phrases & Compounds
Gridiron pendulum
See under Pendulum.
Gridiron valve
a slide valve with several parallel perforations corresponding to openings in the seat on which the valve moves.