Minecraft/Experience
Experience points (or exp. points) are orbs that glow green and yellow. Picking them up causes a green bar above your hotbar to fill up. Picking up a certain amount causes you to level up. As you reach level 9, the amount needed to level up increases with every level.
Exp. is obtained by mining ores, killing mobs , and smelting ores/cooking meat and trading with villagers.
Levels are consumed when you use an anvil or an enchantment table.