The term 'JOIN IN REINDEER GAMES' is a phrase that is used to describe the act of participating IN activities that are fun and festive. It is often used around the holidays, when people are looking for ways to celebrate with friends and family. The crossword solution for this phrase is 'ANY', which is a three-letter word that means 'anyone or anything'. Therefore, the phrase 'JOIN IN REINDEER GAMES' can be interpreted as an invitation to JOIN IN on the fun and festivities of the holiday season.