To check the spelling convention when you're not sure, try this.
1. In G**gle, or your favourite browser, type your mystery word in quotes, and then hit [Enter]. This makes it search on your exact spelling only. Look to see how many pages it finds with that spelling.
2. Now try a different spelling. (It may even suggest an alternative to search). Again, check the page count. What you are looking for is the commonest spelling.
3. Repeat (2) if necessary, for another possible spelling.
4. There may be regional variations. For example, if you want the UK spelling, add uk in the G**gle search box, (but not within the quotes), and select the pages from the UK selector.
5. You may want to check within a technological or scientific field, so include a likely keyword that would narrow the search to that field only.
As a Technical Author, I have used this method for some years, and it works!