ARBE – ׳solidity, grandeur, physical force’

IV.ארבע, four. I have spoken of this word in v. 10 of chapter II; it is needless to repeat. Its root רב involves every idea of strength, of solidity, of greatness, resulting from extent and numerical multiplication.

The root of this mysterious number is רב, which, formed of the sign of movement proper ר, and that of generative action, contains all ideas of grandeur and of multiplication. If the last character is doubled as in רבב, this word acquires an endless numerical extent; if it is followed by the sign of material sense, as in רבע, it becomes the expression of solidity, of physical force, and of all ideas attached to the cube. It is in this state that it represents the number four. But in the above example [Gen. 2:10] it begins one part with the sign of power א, and terminates with the emphatic article ה, which attaches to it the hieroglypic meaning of the four-fold power or quaternary. (The Hebraic Tongue Restored, Fabré d’Olivet, p. 78)