The term 'Jack Squat' is a slang phrase used to describe someone who has no power or influence. The crossword solutions for this term are ZIP (3 letters) and NONE (4 letters). ZIP is an acronym for Zone Improvement Plan, which is the system used by the United States Postal Service to assign postal codes to geographic locations. NONE is a word meaning 'no one' or 'NOTHING'. Together, these two words indicate that Jack Squat has no power or influence in any particular area.