Magazine vs. Clip
A magazine is a spring-loaded ammo-feeding device; a clip merely holds rounds together to load a magazine or cylinder. They are not the same.
A magazine is the spring-loaded container that feeds cartridges into the chamber as the gun cycles — it can be detachable (the box you load into a pistol or AR) or fixed inside the firearm. A clip, by contrast, is a simple strip or holder that keeps rounds together so you can quickly charge a magazine or a revolver cylinder (like a stripper clip or moon clip).
The distinction is a point of pride among shooters: calling a magazine a 'clip' is a common newcomer mistake. Practically, your AR-15 or Glock uses magazines; an M1 Garand uses en-bloc clips; a revolver may use moon clips. Knowing the difference signals familiarity and avoids confusion when buying gear.