What is a raid in wow

Basically, a raid is an instance that is harder than a dungeon, and requires more players to complete (10-25). They have better rewards than dungeons and require players to commit over an hour or more to complete. They are usually best completed with a guild, although there are some players who pug (pick-up group) then when they are bored or their guild doesnt want to run anything.

Raids can only be completed once a week.