No death damage
No death damage is the maximum damage that Link can take without dying even when he would normally not survive. This is used to implement one-hit kill protection.
Calculation
The no death damage value is calculated as follows:
NoDeathDamageBase + floor(PlayerMaxLife × NoDeathDamageAdd) / 4
where NoDeathDamageBase and NoDeathDamageAdd are parameters in Link's bgparamlist. In 1.5.0, those values are 20 (= 5 hearts) and 4 (= 1 heart) respectively.