I would call it a magazine, but in all official documents dealing with the design and adaptation of the 1911, it is a "clip."
I won't argue that, but in all the official documents I have seen and worked with (FM's TM's, etc.), which all date from the WWII era on, it is called a "magazine", and in the shop manuals, a "magazine assembly". It might have been a clip in the beginning but at some point, it turned into a magazine, which is what it is today.
Yes, there is a lot of overlap, and even some gunmakers have labeled magazines as "clips" (my suspicion is this is done for the benefit of the people who think they are clips, so they can find and buy them).
The debate rages on. For my purposes, I consider a magazine to have a spring, and the spring provides the power to put the ammo in position for the gun to feed it..
Clips, might be a spring, (like the enbloc M1 Garand, or 1/2 moon clips for a revolver) or have one, (like the leaf spring in the Mauser stripper clip, but it is used to retain the ammo in the clip. A clip retains, ammo, relying on either the gun mechanism or manual placement to position the ammo for feeding, IF it does. Stripper clips are used to manually feed rounds into a magazine.
I think this definition avoids most of the confusion, but I'm open to arguments for a different one.