They’re closely related, but not exactly the same word.

• Aperture is the opening that lets light through.
• Diaphragm is the device that forms that opening.
• An adjustable diaphragm made of overlapping blades is commonly called an iris, because it resembles the eye’s iris.

So “iris control” usually means the control that adjusts the iris diaphragm, which changes the aperture size. In many modern lenses, especially cine lenses, that is effectively the same thing users mean by “aperture control.”

The reason you see “iris” more in cinema/video is largely historical terminology: movie-camera users traditionally said iris, while still photographers more often said aperture for the same setting.

There have also been other ways to control light or define an opening, so “iris” can be a bit more specific than “aperture.” For example, some older lenses used fixed plates/strips with holes, and some systems may rely on ND filters instead of a diaphragm to reduce light.

So in most current lens listings, “iris control” isn’t a different feature from aperture control—it’s usually cine-style wording that emphasizes the adjustable diaphragm mechanism.