ADVISER OR ADVISOR? 

Let it first be said that adviser and advisor are both correct. They both have the same meaning and are nouns that refer to a person who advises or gives advice. The Oxford English Dictionary gives adviser as the preferred spelling and advisor as a correct alternative.

However, we may well ask why there are two forms of spelling if both have the same meaning. There is no general agreement as to which spelling is older, but most sources claim that that adviser is older. In a more general sense, the ‘-or’ ending is from a Latin origin, while the ‘-er’ ending is from a Germanic origin. There are other nouns that serve the same function as adviser/advisor, some of which end in ‘-er’ and others in ‘-or’. Examples of ‘-er’ endings are teacher, player, runner, driver, while examples ending in ‘-or’ are auditor, conductor, creator, actor. These nouns do not have alternative spellings, as does adviser/advisor. 

So how does a writer decide which spelling to use? Are there any circumstances when one spelling is preferable to the other? It is best to use adviser because this spelling is the most frequently used in literature. Nevertheless, advisor is sometimes considered more formal than adviser, and some writers tend to use the ‘-or’ spelling in formal and academic writing. Although both British and American English generally prefer adviser, the advisor spelling is often used in official titles such as ‘The Military Advisor to the President’. This is particularly the case in American and Canadian English. 

As in all writing, consistency is paramount. Therefore, writers are advised to decide which spelling they prefer, and to use the same spelling throughout the document. It is very unprofessional to use both spellings.  

Finally, it is important to note that although adviser and advisor are both correct (provided of course that there is consistency), the different spellings of advice and advise are not alternatives. The word advice is a noun, an example being ‘The professor gave advice to the students.’ The word advise is a verb, an example of which is ‘The professor advised the students to devote more time to their studies.’