Gear in Hogwarts Legacy are special wearable items that increase your defensive or offensive capabilities. Using the Identification Station, you can identify new gear. Gear comes in different tiers of rarity, currently we know of superb, extraordinary, and legendary.
You can also use the Loom to add traits to your gear. This will also cost you materials, and you can add traits whenever the item has a free trait slot. It is unknown if you can remove traits, or if some items can have multiple traits.