Defn: An aspect of two planets with regard to the earth when they are distant from each other ninety degrees, or the fourth of a circle. Hutton.

TETRAGONAL
Te*trag"o*nal, a.

1. (Geom.)

Defn: Of or pertaining to a tetragon; having four angles or sides; thus, the square, the parallelogram, the rhombus, and the trapezium are tetragonal fingers.

2. (Bot.)

Defn: Having four prominent longitudinal angles.

3. (Crystallog.)

Defn: Designating, or belonging to, a certain system of crystallization; dimetric. See Tetragonal system, under Crystallization.

TETRAGRAMMATON
Tet`ra*gram"ma*ton, n. Etym: [NL., fr. Gr. Tetra-) +

Defn: The mystic number four, which was often symbolized to represent the Deity, whose name was expressed by four letters among some ancient nations; as, the Hebrew JeHoVaH, Greek qeo`s, Latin deus, etc.