The rate at which someone or something is able to move or operate. Rapidity of movement or action. Each of the possible gear ratios of a bicycle or motor vehicle. The light-gathering power or f-number of a camera lens. An amphetamine drug, especially methamphetamine. Something that matches one's tastes or inclinations. Success; prosperity. Move quickly. Make prosperous or successful. Take or be under the influence of an amphetamine drug.