The term '50s Sitcom Staple' can be summarized as a reference to the popular sitcoms of the 1950s, which were often centered around a father figure. The crossword solution for this term is 'DAD', which is a three-letter word that is commonly used to refer to a male parent or guardian. This term is indicative of the traditional family structure that was often portrayed in 1950s sitcoms, with a father figure at the head of the household.