G.I. Doll is a term used to refer to a type of doll that was popular in the 1940s and 1950s. The doll was designed to resemble a soldier, and its name stands for 'Government Issue'. The doll was often given to children as a way to honor their fathers or other family members who served in the military. JOE, which is the 3 letter solution to the crossword, is a common nickname for Joseph, which is a popular name for a soldier.