What is off-sides in lacrosse?

Answer 1

offsides is when the defense or attack cross the mid line* but there are exception with the defense like if a middie stays behind the midline the defense person can go across this is called middie back

*There must be a certain number of players on each side of the mid line per team, which is the reason for offsides. (the number of players mandatory on each side per team varies)

Each team has to have 4 players in their Defensive end and 3 players in there offensive end. If a team has less then 4 or 3 respectively this would be offsides. Any player including long pole, goalie, mid field or attack can cross the middle line as long the side they are leaving has the correct number of players remaining. Although not common a goalie could technically go end to end all over the field with being penalized for offsides.

So for example if a player crosses the middle line leaving less the minimum number of players remaining in the end that team would be penalized for the infraction with either a loss of possession or a 30 second technical penalty.