Name of a certain modern rear-derailleur part at upper end of pivot Some derailleurs, particularly "old style" drop-out-mounted ones have a pivot whose upper end is a kind of combination joint: it has a bushing that allows the pivot to rotate, under spring action, and that joint also has attachments for the pivot's parallelogram members.

Newer style direct-mount derailleurs (but even new drop-out-mount ones like the Shimano RD-TX55) elongate this upper joint of the pivot into a small member. The rotating bushing is on the upper end of this member (rotating around the mounting bolt on the DM units), and the parallelogram members attach at the lower end of this member.

Does this member have a special name? Is it considered part of the pivot, or are only the parallelogram arms "the pivot"?

For that matter, does the original "combination joint" have a name, and is it considered separate from the pivot?
If it's the part I think you mean, Shimano label it as either the Bracket Axel Unit or the B-Axel depending on if it's the direct mount or standard mount variant.