Meld with nature

Meld with nature makes faeriekin immune to all effects except for AoE attacks. My question is, what constitutes an "effect?" Is that any ability, or specific types of abilities? I couldn't find a definition of "effect" in the book.

An effect would be any attack or other ability that targets the character. So while melded you would be unaffected by any attack, environmental effect, spell, skill, ability, etc. used against you, unless it is an Area Effect.