Elemental refers to a type of magic wielded by shamans. It is a multi-school, combining the Fire, Frost and Nature schools. Multi-school abilities benefit from bonuses that affect any of their schools, use the lowest resistance value among their schools, ignore absorption and immunity effects that apply to only some of their schools, and can be used even when one or more of their schools have been locked with an interrupt effect. For example, 
[Elemental Blast] is counted as a Nature spell for the purpose of 
[Maelstrom Weapon].
Elemental spells
Shaman:
Patch changes
Patch 5.0.4 (2012-08-28): School added, with the introduction of [Elemental Blast].