What's the difference between priority and speed?

Question

Title says all

Answer 1

Priority (Japanese: 先制 preemption) is a characteristic of moves, such that any move with a higher priority than another will always be performed first. When two moves have the same priority, the users' Speed statistics will determine which one is performed first in a battle. Each move has a hidden priority value in the game data, with values ranging from +5 to -7. The great majority of moves have no special priority: their priority value is 0. A move with a positive priority is a priority move (Japanese: 先制攻撃 preemptive attack).

The Speed stat (Japanese: 素早さ能力 speed ability) determines the order of Pokémon that can act in battle. Pokémon with higher Speed at the start of any turn will generally make a move before ones with lower Speed; in the case that two Pokémon have the same Speed, one of them will randomly go first.

Speed also determines the order of other things, such as which abilities activate first and which Pokemon get hurt by poison first. Trick room reverses the order of moves in the same priority bracket, but the order of priority brackets stay the same.

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Answer 2

Speed is the actual speed stat. Priority is the speed the move moves at. For example, moves like Flamethrower and Draco Meteor have a priority of 0, while moves like Quick Attack, Bullet Punch, Aqua Jet, and Water Shuriken have a priority of 1. Fake Out has 3 priority and Extreme Speed has a priority of 2