Plumbing, mechanics: what is a flange?

Self-tutoring about fastening elements in mechanical or plumbing systems: the tutor mentions the idea of a flange.

The following is according to my understanding.

A flange is an extension from a conduit or a structural component, aka the hardware. The flange facilitates fastening its associated hardware to another piece of hardware, often to the flange of the other piece of hardware.

A flange will often have bolt holes in it or else welding will hold it. In its context, the flange will often be wide and flat, giving lots of surface area for a strong connection. Fastening is done to the flange, so that the fastening doesn’t get in the way of the function of the associated hardware.

Source:

tameson.com: Pipe Flange Types and Working Principle

YouTube: Radwell International: What is a Flange?