The term 'Sign of Success' can be represented by three different crossword solutions: SOLD (4 letters), VEE (3 letters), and SRO (3 letters). SOLD stands for 'SOLD out', which is a phrase used to describe when all tickets for an event have been SOLD. VEE is short for 'VICTORY', which is a sign of success in many contexts. Finally, SRO stands for 'standing room only', which is another phrase used to describe when all tickets for an event have been SOLD. All three of these terms are indicative of success, as they demonstrate that an event has been popular enough to sell out.