Is OJ a scrabble word?

Is ET a 2 letter scrabble word?

Ew joins another 106 two-letter words, which are aa, ab, ad, ae, ag, ah, ai, al, am, an, ar, as, at, aw, ax, ay, ba, be, bi, bo, by, da, de, do, ed, ef, eh, el, em, en, er, es, et, ex, fa, fe, gi, go, ha, he, hi, hm, ho, id, if, in, is, it, jo, ka, ki, la, li, lo, ma, me, mi, mm, mo, mu, my, na, ne, no, nu, od, oe, of, ...