Frames are what measure the speed of attacks in fighting games. The fewer the frames, the faster the attack in question. Each second is divided into sixty frames.
Say, for example, you have a five-frame attack and your opponent has a seven-frame attack. Yours will be faster in that scenario, provided you're within range for the move to connect.
Frames vary between different characters and how their attacks work, so it's recommended to study up on the concept of frame data to improve your character knowledge.
