Lifelink

Lifelink is a keyword ability introduced in Future Sight. The Lifelink keyword, fear, and the vigilance keyword are the only keywords with a card of the exact name. Flying comes close, with the card called Flight.

702.14. Lifelink
- 702.14a Lifelink is a static ability.
- 702.14b Damage dealt by a source with lifelink causes that source’s controller, or its owner if it has no controller, to gain that much life (in addition to any other results that damage causes). See rule 119.3.
- 702.14c If a permanent leaves the battlefield before an effect causes it to deal damage, its last known information is used to determine whether it had lifelink.
- 702.14d The lifelink rules function no matter what zone an object with lifelink deals damage from.
- 702.14e Multiple instances of lifelink on the same object are redundant.

Rulings

The ability causes life gain whenever a permanent with lifelink deals any damage, not just combat damage.
The life is gained as a state-based effect.
All older cards with the ability "Whenever this permanent deals damage, you gain that much life." that received errata to change that ability to "lifelink" have reverted to their original wording with the exception of Loxodon Warhammer, which had been printed with the word "lifelink" on its most recent printing in 10th Edition.
Note that the card Spirit Link does not grant the creature it enchants lifelink. The lifelink ability has the creature's controller gain life. Spirit Link has Spirit Link's controller gain life. The same is true for Vampiric Link.

The latest reminder text for Lifelink reads "Damage dealt by the creature also causes its controller to gain that much life."

Caravan Hurda -
Creature — Giant
1/5
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

One creature