Healing area is specific part of a level(usually around shrines/temples) that heals player's character with a slow rate. Additional function might include reducing curse/debuffs or removing poison duration.
A.Active-use "Healing Well": unlimited percentage healing/mana recharge by clicking
B.Active-use "Limited Shrine": usually fully heals or adds a strong buff, inactive until recharge period ends. One click use.
C.Passive-use "Healing area": passively adds HP/Mana stats (slowly).
D.Passive-use "Rechargeable area": fully heals but inactive unti recharge period ends.
E.Passive-use "Buff-area": adds a buff to character passing through(typically resistances)
F.Passive-use "Aura of the place": adds a specific aura to characters inside the area(typically healing / recharging stats).