Not just horizontal or vertical or diagonal, but all the -als. Sometimes seen in the specifically geological sense of dipping in all directions from a central peak, but really, it deserves to more universal use. The hedgehog curled up to display its quaquaversal spines. This company has a quaquaversal strategy and needs to focus on its core business. In a panic, I ran quaquaversally 'round the house, trying to get ready to leave.
My one problem with the word is that for many years I was pronouncing the first two as the same -- but despite coming from Latin quāquā versus (adopted in the 1720s), where they are the same vowel, in English the first is long and the second short.