[caf]

What UNIX called an inode is unfortunately not what Linux now calls an inode. That thing might have better names, but we are stuck with it.

How so? Here's a v6 on-disk inode: https://github.com/hephaex/unix-v6/blob/master/ino.h

and here's an ext4 on-disk inode: http://lxr.free-electrons.com/source/fs/ext4/ext4.h#L704

The latter is considerably larger, to be sure, but still contains all of the fields from the former (many of them with the same name!).

[geocar]

That may be, but Linux also uses the term "inode" to refer to what the BSD's refer to as a "vnode", which also have similar names.

[caf]

UNIX v6 used the term "inode" to refer to that as well - it was BSD that changed the name.

UNIX called them "inode" and "permanent inode"; Linux calls them "in-memory inode" and "on-disk inode". The BSDs use "vnode" and "inode".