The only two-letter English word that starts with Z is "za." It is a slang word that means pizza. Za is also the 17th letter of the Arabic alphabet.
Coined by college students, the term "za" first originated in 1968 in the United States.
Za is allowed in both Scrabble and Words with Friends. Some proper names may also be two letters long and start with Z, but they are not permitted in those games. However, several three-letter words begin with Z, including "zoo," "zit," "zip," "Zen" and "zig." Zoa and zee are two lesser-known words, but they are also acceptable for Scrabble and Words with Friends.