I had a discussion with a recruiter recently that made me wish I could visually represent programming skills. In trying to explain how skills relate, what are the important properties of those skills? Would a tagging model work (i.e. "Design Pattern," "Programming Language," "IDE," or "VCS")? Are they really hierarchical?

Clarification: The real problem I see is communicating the level of granularity among skill sets. For instance saying someone "knows Java" is a uselessly broad term in describing what someone can DO. However saying they know how to write web services with the Java Programming language is a bit better. To go even further, saying they know Spring as a tool under all that is probably specific enough.

What should we call those levels of granularity?

What are the relationships between the terms we use? i.e. Framework to Language, Tool to Language, Framework to Solution(like web services), etc.