What exactly is a "death effect"

[AuraSeer]

wouldn't an easier way to describe a 'death effect' be: whatever is affected by the spell Death Ward?

Easier, yes, but it wouldn't be informative. Death Ward states that it protects against death effects, so if we define death effects as things against which the spell protects, we end up with a circular definition.

It'd be as if as if you defined the word "ball" to mean "something round," and the word "round" to mean "ball-shaped." Unless you already know what one or the other means, neither definition is any help.

 

[Sejs]

Spells from the PHB that would be negated by Death Ward:

Circle of Death
Death Knell
Destruction
Finger of Death
Power Word, Kill
Slay Living
Symbol of Death (not listed, but fits the bill)
Wail of the Banshee

Additionally, I'd allow magic items that process the above spells to have their effects negated. Examples:

Vorpal weapons
Arrow of Slaying
Mask of the Skull
Necklace of Strangulation
Scarab of Death

 

[Mr Fidgit]

Easier, yes, but it wouldn't be informative. Death Ward states that it protects against death effects, so if we define death effects as things against which the spell protects, we end up with a circular definition.

i see what you mean, but i thought it might help a little (especially because it says not all 'lethal' effects are death effects...)