You are bleeding out or otherwise at death's door. While you have this condition, you are unconscious. Dying always includes a value, and if it ever reaches dying 4, you die. When you're dying, you must attempt a recovery check (page 411) at the start of your turn each round to determine whether you get better or worse. Your dying condition increases by 1 if you take damage while dying, or by 2 if you take damage from an enemy's critical hit or a critical failure on your save.
If you lose the dying condition by succeeding at a recovery check and are still at 0 Hit Points, you remain unconscious, but you can wake up as described in that condition. You lose the dying condition automatically and wake up if you ever have 1 Hit Point or more.
Any time you lose the dying condition, you gain the wounded 1 condition, or increase your wounded condition value by 1 if you already have that condition.
Death and Dying conditions
Player Core groups Dying with Doomed, Unconscious, Wounded.
Source: Pathfinder Player Core, p. 443
Bring Dying into a Pathfinder 2e game with The DM Screen.