The term Greek I's is a reference to the Greek letter Iota, which is the ninth letter of the Greek alphabet. Iota is often used to represent the number 10 in mathematics and is also used in various scientific fields. In addition, Iota is also used in some religious contexts, such as in the Bible, where it is used to refer to the tenth letter of the Hebrew alphabet. In the crossword puzzle, the term Greek I's refers to the letter Iota, which is represented by the five-letter word 'IOTAS'.