Damage over time, abbreviated DoT, is a term commonly used to describe skills that distribute damage to their target over a period time, rather than all at once.
There are two types of damage over time:
- Repeated damage in small discontinuous portions, usually each second, for a certain amount of time, as caused by Balthazar's Aura, Chaos Storm, Eruption and many other spells, especially AoE spells.
- Continous health degeneration, such as inflicted by Conjure Phantasm or conditions like bleeding and burning, expressed as arrows pointing left on the health bar. Note that technically the game does not consider health degeneration as damage.
An important consequence of the difference between these two is that in the former case, each portion of damage counts individually, so protective spells like Shielding Hands or armor that "reduces damage" will reduce each small portion. These portions will also trigger spells which activate upon taking damage, such as Healing Seed or Balthazar's Spirit, but continous health degeneration will not trigger an effect at all.
When people say "damage over time" they may mean both types or only one of the two.