The holy of holies was divided, as to its cubical contents, by the placing of the cherubims. There seems to be no especial meaning to this word, fitting it for such a place. The meanings usually assigned, though prehaps proper enough, after a fashion, as man, angel, cherub, are really not proper to the term. The word comes from Kaph-Resh-Beth = C-R-B = C*r*b, or Carab, meaning prehensile, to seize, grasp, as with talons...; as substantive it means bird...it is the British word crab, that seizes with its circular pincers,; also the word grab, as closing your fingers on something.... The real value of the word is thought to be in its numerical value, which is Kaph=20, Resh=200, Beth=2, or in a total of 222. These cherubims were 10 cubits in height, and stood with outstretched wings of 5 cubits in length, each touching, as to each, the wall upon one side, and the tip of the wing of the other, in the midst.

- From The Source of Measures, by J. Ralston Skinner

Therefore, there are always two cherubim, or 2x222=444, which is Daleth, or the Door.