In the past, I have tended to use the term "rating" for characteristics. Abilities in Omnia may be rated from 1 to 6, and the result is a rating, right? The problem, though, is that "rating" makes one think of popularity or personal opinion, but Abilities are supposed to be an objective evaluation. I am already using the term "score" for Health, Psyche, and Luck, so why not extend that to Abilities? A score in Omnia game terms is simply an expression of capability. It's a natural fit.