Map Difficulty
From WikiName
Maps are categorized by a range of difficulty levels.
Contents
Newbie
A character with has less than two classes at level less than 20.
Lowbie
A character that is less than 8x20
Mid
A character that is less than 3x40 ( three classes to level 40 )
High
A character that is not Avatar 40
Very High
A characters should be at least Avatar 40.
Group Modifier
A difficulty might also have the modifier Group which indicates that you would need a group of characters, usually more than 4 in the same level range in order to survive encounters in the area.