Revivify

3rd-Level Necromancy Spell (Cleric, Druid, Paladin, Ranger)

Casting Time: Action
Range: Touch
Components: V, S, M (a diamond worth 300+ GP, which the spell consumes)
Duration: Instantaneous

You touch a creature that has died within the last minute. That creature revives with 1

Hit Points (HP) are a measure of how difficult it is to kill or destroy a creature or an object. Damage reduces Hit Points, and healing restores them. You can't have more Hit Points than your Hit Point maximum, and you can't have less than 0. See also Breaking Objects and Damage and Healing.

. This spell can't revive a creature that has died of old age, nor does it restore any missing body parts.

Source: Player's Handbook, p. 312