Lightning damage is one of the five Damage Types. It is reduced by Lightning Resistance. Lightning hits have a chance to Shock based on how much Lightning damage is dealt.

Ailments are a family of common Debuffs associated with specific damage types. The list of Ailments is: Bleeding, Ignite, Chill, Freeze, Shock, Electrocute, and Poison.

Bleeding is an Ailment that deals Physical damage over time, and lasts 5 seconds by default. Damage from Bleeding bypasses Energy Shield

Bleeding deals an extra 100% damage while the target is moving, or if the Bleeding is Aggravated.

Physical damage from Hits Contributes to Bleeding Magnitude.

Damage does not Contribute to Bleeding chance, so it cannot be inflicted without an explicit source of Bleeding chance.

The base Magnitude of Bleeding is Physical damage per second equal to 15% of the Pre-mitigation Physical damage of the Hit that inflicted it. This magnitude is not further affected by any modifiers to the damage you deal.

Modifiers and Debuffs that affect the enemy's ability to mitigate damage (such as Shock) can affect the damage the enemy takes from Bleeding, but any such modifiers that specifically apply to Hit damage (such as Armour Break) do not affect Bleeding damage.

Elemental Ailments are Ignite, Chill, Freeze, Shock, and Electrocute.

Ignite is an Ailment that deals Fire damage over time, and lasts for 4 seconds by default.

The chance for a Hit to Ignite a target is determined by the total Magnitude of Flammability on the target, including the amount added by that Hit.

Fire damage from Hits Contributes to the Magnitude of Ignite, so Hits dealing more Fire damage inflict stronger Ignites.
The base Magnitude of Ignite is Fire damage per second equal to 20% of the Fire damage dealt by the Hit that inflicted it. This is calculated using the final damage dealt by the Hit, but not any modifiers on the target that affect how much damage they will take from the Hit. This Magnitude is not further affected by any modifiers to the damage you deal.

Modifiers and Debuffs that affect the enemy's ability to mitigate damage (such as Shock) can affect the damage the enemy takes from Ignite, but any such modifiers that specifically apply to Hit damage (such as Penetration) do not affect Ignite damage.

Ailments that do not deal damage are Chill, Freeze, Shock, and Electrocute.

Poison is an Ailment that deals Chaos damage over time, and lasts 2 seconds by default. Damage from Poison bypasses Energy Shield.

Physical and Chaos damage from Hits Contribute to Poison Magnitude.

Damage does not Contribute to Poison chance, so it cannot be inflicted without an explicit source of Poison chance.

The base Magnitude of Poison is Chaos damage per second equal to 20% of the Pre-mitigation Physical and Chaos damage of the Hit that inflicted it. This magnitude is not further affected by any modifiers to the damage you deal.

Modifiers and Debuffs that affect the enemy's ability to mitigate damage (such as Shock) can affect the damage the enemy takes from Poison, but any such modifiers that specifically apply to Hit damage (such as Penetration) do not affect Poison damage.

Shocked Ground Shocks those standing in it, and lasts 6 seconds by default.

Damage can be converted from one type to another. This causes it to deal the new damage type, scale with modifiers to the new damage type, and no longer scale with modifiers to the old damage type.

For example, Fire damage converted to Lightning now scales with Lightning damage modifiers and causes Shock, but no longer scales with Fire damage modifiers or causes Ignite.

Conversion is a two step process. Conversion inherent to Skills occurs first, then Conversion from all other sources. Damage over time cannot be converted.

Shock and Electrocute are Lightning Ailments.

Chilling Enemies grants 1 Unbound Fury, Shocking or Igniting Enemies grants 2 Unbound Fury and Freezing or Electrocuting Enemies grants 6 Unbound Fury.

Lightning Archon is a type of Archon Buff.
Lightning Archon grants:
25% more Lightning Damage with Spells
Convert 100% of Elemental Damage with Spells to Lightning Damage
Cannot deal Non-Lightning Damage with Spells
Hits with Spells have 100% more Shock chance

While affected by Unravelling, your Chaos Damage randomly either also contributes to Freeze buildup, Flammability and Ignite Magnitudes, or Shock chance - changing which it contributes to every two seconds.