Pathfinder 2e uses a system of “tags” on nearly every noun in the game. Actions, ancestries, feats, items, spells, they all have tags. These tags both describe and categories the various rules entities.
Some tags don’t have an affect on their own, but might interact with other features in the game. For example, a feat might grant a damage bonus to all spells with the “fire” tag.
Some tags have specific mechanical effects. For example: The “uncommon” and “rare” tags indicate the rarity of an item (more on rarity later in these articles), while spells might have tags like “fire” or “polymorph”.