1. The mystic number four, symbolically representing the Deity, whose name, in most ancient languages, was expressed by four letters; as Dens, Alia, &c.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• retragrammaton,
• fetragrammaton,
• getragrammaton,
• yetragrammaton,
• 6etragrammaton,
• 5etragrammaton,
• twtragrammaton,
• tstragrammaton,
• tdtragrammaton,
• trtragrammaton,
• t4tragrammaton,
• tetagrammaton,
• tetragammaton,
• tetragramaton,
• tetragrammton,
• tetra grammaton,
• Tetragrammatan,
• TetraGramman,
• Tetragramatun,
• TetraGrammon

The adjective form of the word "tetragrammaton" is "tetragrammatic".

The plural form of the word "tetragrammaton" is "tetragrammatons".

The singular form of the word "tetragrammaton" is "tetragrammaton". The word itself refers to a Hebrew word that is composed of four letters and is often used to represent the name of God in Jewish tradition.