Favored is the American spelling of favoured. British English, and a lot of school English in Taiwan, keep the u: favoured. The meaning does not change with the spelling. It means given extra kindness, help, or a better deal — a favored child gets more love; a most-favored-nation rule gives a country better trade terms. It is the -ed form of favor / favour. Though actually, students sometimes slide it toward favorite, "the one I like best." Favorite / favourite is a different word in the same family. Pick British or American spelling and stay with it on the page.