Orthogonal

In recent arguments before the Supreme Court some lawyer used the word "orthogonal" in a way that I thought was a pretty natural meaning. (see Simple Justice, Washington Post, or Althouse.

MR. FRIEDMAN: I think that issue is entirely orthogonal to the issue here because the Commonwealth is acknowledging -
CHIEF JUSTICE ROBERTS: I’m sorry. Entirely what?
MR. FRIEDMAN: Orthogonal. Right angle. Unrelated. Irrelevant.
CHIEF JUSTICE ROBERTS: Oh.
JUSTICE SCALIA: What was that adjective? I liked that.
MR. FRIEDMAN: Orthogonal.
CHIEF JUSTICE ROBERTS: Orthogonal.
MR. FRIEDMAN: Right, right.
JUSTICE SCALIA: Orthogonal, ooh.

I was going to make a post about what dummies we have on the Supreme Court until I mentioned it to my girlfriend (whose degree is in psychology but she's still not a dummy) and she said, "Huh, what does that mean?".

So I guess the dummy is me, the one that just assumed that if it's a word I've commonly used it must be a word that everyone knows.