Tetragonal and Four

adjective

• Of or relating to or shaped like a quadrilateral. .

• (a.) Of or pertaining to a tetragon; having four angles or sides; thus, the square, the parallelogram, the rhombus, and the trapezium are tetragonal fingers.
• (a.) Designating or belonging to, a certain system of crystallization; dimetric. See Tetragonal system, under Crystallization.
• (a.) Having four prominent longitudinal angles.

• (n.) A symbol representing four units, as 4 or iv.
• (n.) Four things of the same kind, especially four horses; as, a chariot and four.
• (n.) The sum of four units; four units or objects.
• (a.) One more than three; twice two.

noun

• The cardinal number that is the sum of three and one.
  • synonyms: 4, IV, tetrad, quatern, quaternion, quaternary, quaternity, quartet, quadruplet, foursome, Little Joe
• A playing card or domino or die whose upward face shows four pips.
  • synonyms: four-spot

adjective

• Being one more than three.
  • synonyms: 4, iv