What is the shortest word in Scrabble?

The shortest word in Scrabble is not one single word but many 2 letter words, as 2 letter words are the shortest valid words allowed in Scrabble; 1 letter words are not allowed except that A and I are valid 1 letter words in some dictionaries but not in official Scrabble play where minimum length is 2. The official Scrabble lexicon includes over 100 two letter words that are extremely important for strategic play, as they allow you to play parallel to existing words and score in tight spaces. Examples of the shortest words include AA which is a type of lava, AB, AD, AE, AG, AH, AI, AL, AM, AN, AR, AS, AT, AW, AX, AY, BA, BE, BI, BO, BY, DE, DO, ED, EF, EL, EM, EN, ER, ES, ET, EX, FA, FE, 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, OH, OI, OK, OM, ON, OP, OR, OS, OW, OX, OY, PA, PE, PI, QI which is the only Q without U two letter word, RE, SH, SI, SO, TA, TI, TO, UH, UM, UN, UP, US, UT, WE, WO, XI, XU, YA, YE, YO, ZA. These 2 letter words are the shortest playable words.