Rename it to “Acid resistance” to be consistent with the elemental equivalents. Or rename the others to “Burn and fire resistance” etc. but that’s verbose.
No otherwise they need to make another type of resist called Poison resistance… and then go through all the gear/skill/devotion to balance the resistances for Acid resistance and Poison resistance. In the end it would take way too much work to add absolutly nothing gameplay wise. On top of that we have more than enough resistances to cover as it is!
It’s two type of damage within one resistance.
You’re misunderstanding. The OP is wondering why “poison and acid resistance” specifies both when other resistances just say “fire”, “cold”, etc. without specifying the damage-over-time equivalent like burning and frostburn. It’s a semantic suggestion rather than a gameplay suggestion.
I most be tired…
And i was’t refering to the gameplay itself but mainly to the fact that at this point in the developpement, even if i was a bit off :P, adding another resistance wouln’d have added anything gameplay wise… but just complexity to manage resistances.
But, I misread… i guess
Snazzblaster gets it 
On the other hand, acid and poison are different things, even though they’re both liquids that kill you, so I get the reasoning behind naming it “Poison & Acid Resistance”. Burning is obviously ongoing fire, and electrocution is obviously ongoing electricity, so that kinda makes my original point weak. Still something to think about.
because the average human relates fire and burn automatically, but not acid and poison…
I get the impression it’s named so because Poison was carried forward from TQ and had Acid added to it as a direct damage type in this game, hence Poison and Acid.