Type

Types are properties that define a Pokémon and its moves. There are 22 official types, as listed on the right. There are 2 pseudo-types that a Pokémon can have temporarily, with the exception of Porygon and its evolutions.

Ambient introduces five new types:

A Pokémon and its moves can have up to two types, a primary and a secondary. A damaging moves' type(s) determine how effective it will be against certain Pokémon type(s).

Type effectiveness
Damaging moves can vary in effectiveness depending on its typing and the typing of its target. This will greatly influence how much damage is dealt and how move effects will be affected.

List of effectiveness
Such as Muddy Water, a Water-type and Ground-type move, being used on a Magcargo, a Fire-type and Rock-type will deal massive amounts of damage, especially if used by a Pokémon like Quagsire.

Type chart
This is a type matchup chart displaying how type modifiers are applied to a move type(s) when attacking Pokémon of each type. If the target is dual-type, the modifier is applied to both.

Trivia

 * Steel-type was renamed to Metal-type by Professor Palm, classified in her research as "...an alteration based on the composition of every metallic-coated Pokémon, whether it be iron or steel." A copy of this research thesis is publicly available at the PokéUniversity library in Silk City.