Two letter words with X are extremely rare, but they do exist. Examples include ‘XI’, ‘XU’, ‘XY’, and ‘XA’. These words have a variety of different uses in the English language depending on context, with ‘XI’ being used to represent the 14th letter of the Greek alphabet, while ‘XU’ is an informal word for cash and is sometimes used when referring to money in certain Southeast Asian countries. Meanwhile, ‘XY’ serves as a variable name for math equations or functions and can also be used as an abbreviation for ‘x-ray’. Lastly, the word ‘XA’ is considered a crossword puzzle answer and is most often found in this context.