What do you call a cutting feature that is produced on the interior surface of a cylindrical part?

The term that best describes a cutting feature produced on the interior surface of a cylindrical part is "groove." In machining, grooves are typically defined as features that have been cut into a surface and are characterized by being deeper than a channel but more narrow compared to a cavity. They can serve various functions, such as accommodating seals or retaining rings in assemblies.

Channels, on the other hand, usually refer to wider cuts or passages intended for fluid flow or other functions. A cavity is often a larger, more open space within a part that serves different purposes, such as weight reduction or housing components. Lastly, a fillet is a curved transition between surfaces, meant to reduce stress concentrations and improve part strength, but does not describe a feature within the interior of a cylindrical part. Understanding these distinctions is key in the context of machining and design.