Who's there?' is a common phrase used to initiate a conversation. It can be used as a greeting, or to ask for identification when someone is at the door. The crossword solutions for this term are ATTENDEES (9 letters), ATTENDANCE (10 letters), FIRST (5 letters), FIRSTBASE (9 letters), and UNITEDNATIONS (13 letters). ATTENDEES refers to people who are present at an event, while ATTENDANCE is the act of being present. FIRST is an adjective meaning 'before all others in time or order, ' and FIRSTBASE is a position in baseball. Finally, UNITEDNATIONS is an international organization that works to promote peace and security around the world.