Is the terminology of "small knight's approach", (or keima kakari) really limited to the corner?
Perhaps. My personal terminology may differ from that of others.
If someone says they made a keima kakari to a 4-3 stone, i expect this one:
Think language, not logic. In language we develop shorthand expressions that are ambiguous on their face. That happens all the time. It happened with joseki. For instance, the one space pincer joseki -- not just the one space pincer -- refers specifically to this joseki:
In the linguistic shorthand these first two moves are assumed. They are defaults. If you want to refer to a different joseki with a one space pincer, you have to be more specific.
You can complain about the ambiguity if you want to, but the use of defaults makes language more efficient. :)
For joseki, the third line is the default. So knight's approach, without any other specification, means an approach on the third line. Also, without any other specification, it means an approach to a 3-4 stone.