What do U11, U13, U15 and U19 mean?
These are abbreviations used by US Lacrosse that mean Under 11 years old, Under 13 years old, Under 15 years old and Under 19 years old. In order to be eligible for a certain age category, for example U15, a player must not be 15 years of age on or before December 31, 2007 to play on a U15 team in a 2008 tournament.