Elemental Damage or Elements in Monster Hunter World (MHW) refers to the secondary damage done by Weapons and monsters - checking against specific resistances on both players and AI enemies. Please see Status Effects to understand Abnormal Statuses, that have a buildup before they deal damage.
Element Damage in MHW
Each monster has weaknesses that will cause it to take more damage. For example a fire monster will take more elemental damage from weapons that deal water damage but less or zero damage from weapons that deal fire elemental damage. Monsters can also deal elemental damage to the hunter. Armor with high resistances to certain elements will cause you to take less damage and reduce the chances of getting elemental blights.
- Elemental weakness is not always a given. Just because a monster uses fire does not mean it is weak to water. Furthermore, monsters that don't use elemental attacks still have elemental resistances and weaknesses. You can push the Start or Options button from there find Hunters Notes then open up the Monster Field Guide and from there go to the monsters Physiology to look up their elemental weaknesses, some monsters have semipermanent opposite resistances on them because of what type of breakable defense they have on them, like mud that can be removed to reveal thunder and/or fire resistance weaknesses, while water resistance will be ignored afterwards, until they cover themselves with mud again.
- Some monsters will have multiple resistances or have multiple elemental attacks. Some weapons might have mixed elemental damage as well.
- Poison, Sleep, Paralysis, Blast and Stun are Abnormal Status Effects. They do not deal damage each hit, but rather imagine a gauge that fills up and once full creates a status, and that status is the one that has an effect.
Note: Some weapons have elemental damage that is grayed out and in parentheses. These weapons require a skill called Free Elem/Ammo Up in order for you to use it.
Types of Elemental Damage
Fire Element - The Fire element is usually strong against Ice but weak to Water. Taking fire damage can cause Fireblight, which lowers the red part of the health bar before reducing the green health bar. This can be removed by rolling repeatedly. Rolling through water will remove it instantly.
Dragon Element - The Dragon element is quite a bit different from other elements. Its the only element in the game that is usually weak to itself. Frequently, it is also weak to Thunder and Ice. Taking Dragon damage can cause Dragonblight which can lower weapon affinity, competely remove a weapon's elemental damage, and even lower the special attack ratings on poison, paralysis, sleep, and slime/blast.