Advisor
WordNet
noun
(1) An expert who gives advice
"An adviser helped students select their courses"
"The United States sent military advisors to Guatemala"
WiktionaryText
Usage notes
In the UK, Ireland and Asia the spelling is traditionally adviser, though US spelling advisor is becoming increasingly common. In the US, Associated Press style is adviser, and most newspapers and some magazines follow that spelling, while US federal government style, other government agencies, and many businesses prefer advisor. News organizations around the world may change spelling found in sources, even in quoted material. US book publishers may be less likely to change spelling in quoted material because the practice is contrary to The Chicago Manual of Style.