We thought at first that it was a misprint but it really seems that "orghogonal" or "orghonormal" (with a g) means something different from "orthogonal" or "orthonormal" (with a t). Do you know where we can find a precise definition ?
I think it's a typo. It's probably rather more common than other typos, because the letters "t,h,g" are very close to each other on a standard keyboard. As a result, it actually does appear in the literature rather more often than you'd expect, and always without definition.
(As such, I believe this post qualifies as a legitimate research question and shouldn't be closed, despite the fact that it's about a trivial typographical error. Hilarious!)
For instance, here it is in a google books search result. It appears in the second page of an article in a collection of proceedings of a conference, without any definition. Elsewhere in the article it seems to be talking about orthogonality.
Of course I'd be happy to be proven wrong - probably the best thing to do is to contact someone who's used the word in print. Maybe they know what it means.