Would just “dimension”, short for “dimension of ability” or “dimension of competence”, work as a term to replace what I was calling a “rankable” competence definition? To me, calling it a dimension does properly imply that there are different places along it, but also sits happily with various different measures of that dimension.

The only drawback I can see is that several competences represent more than one dimension, which have been merged together somehow. That would suggest the word “space” as in “competency space”, which would go well with “positions” in that space.

What do you think?