The depth at which a group in a report or data access page is nested inside other groups. Groups are nested when a set of records is grouped by more than one field, expression, or group record source. The first field, expression, or group record source you sort or group on is level 0; you can create as many as 10 group levels in a report and an unlimited number of group levels in a data access page. In other database products, group levels are sometimes referred to as break levels.