'MuricaHa, I'm sorry if the Queen's English offends. In that case... Favor
**Edit** I'm sorry about this but I couldn't resist. Granted that I'm German in background and have no real ties to British English (though in the end it is their language), I wanted to see what origin each spelling came from. What I found on the grammarist.com website I just could not resist posting.
"Favor vs. favour
Favor and favour are different spellings of the same word. Favor is the preferred spelling in American English. Favour is preferred in all other varieties of English."