When you are looking for which terms are more commonly used, Google each term (in quotes) and compare the number of results.
Wireframe has the most results, and it’s use to refer to a commonly understood noun in English also would make it the preferred choice. So use “wireframe”.
The answer you’d get once you migrate this over to the English SE is to look for the comparative usage in modern text corpuses.
In the Corpus of Contemporary American English:
- wireframe occurs 37 times
- wire-frame also 37
- wire frame 28
In the British National Corpus:
- wireframe 24
- wire-frame 0
- wire frame 10
However, if you look at the context in which those are used, you’ll find that they’re referring to actual frames made of wire or to the style of eyeglasses. Wireframe (one word) is generally used in the UX context.
You could also try using Google Fights for comparison if you only care about frequency, but the problem is that this will not take into account the context of usage.
Edit: I just noticed that you tagged your question with “wireframe,” not “wire-frame,” not “wire frame.” That’s probably because the tag has been used 68 times on this site while the other two haven’t been used at all. It looks to me like by posting your question you answered your question.