By Mary Morel
Reader’s question: Which is correct – adviser or advisor?
Answer: Both are acceptable. Some people prefer adviser because adding -er is the more common word ending (e.g. helper, trader). But there are plenty of exceptions (editor, author, doctor).
I have noticed a trend for advisor being used for job titles, e.g. financial advisor (but financial adviser is also used).
As with all words that can be used interchangeably, consistency matters whatever your choice is.
I am not sure it makes any difference to modern usage, but adviser is older than advisor – adviser dates back to the 17th century, whereas advisor was first recorded just before 1900.