savior / saviour are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
savior: (noun) a person who rescues you from harm or danger.
saviour: NA
savior: s·EY·v·y·er
saviour: NA
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)