The term PHILA. ATHLETE is a reference to a professional basketball player from Philadelphia, Pennsylvania. The crossword solution SIXER refers to the Philadelphia 76ers, a professional basketball team in the National Basketball Association (NBA). The Philadelphia 76ers are one of the oldest teams in the NBA and have won three championships since their founding in 1946. As such, the term PHILA. ATHLETE can be used to refer to any professional basketball player who has played for the Philadelphia 76ers.