Anadviser oradvisor is normally a person with more and deeperknowledge in a specific area and usually also includes persons with cross-functional and multidisciplinary expertise. An adviser's role is that of a mentor or guide and differs categorically from that of a task-specific consultant. An adviser is typically part of the leadership, whereasconsultants fulfill functional roles.[1]
The spellingsadviser andadvisor have both been in use since the 16th century.[2]Adviser has always been the more usual spelling, thoughadvisor has gained frequency in recent years and is a common alternative, especially in North America.[3][4]
The use ofadviser is of English origin, with "er" as a noun ending, andadvisor of Latin origin.[5] The words areetymological twincognates and are considered interchangeable.
Usage of the two words is normally a matter of choice, but they should not be used together in the same document. The Associated Press prefers (AP Stylebook) the use of "adviser", butVirginia Tech (style guide) gives preference to "advisor", stating that it "is used more commonly in academe" and that "adviser is acceptable in releases going to organizations that follow AP style".[6]Purdue University Office of Marketing and Media's Editorial Style Guide gives preference to "advisor".[7] TheEuropean Commission uses "adviser(s)",[8] theUK hasSpecial advisers, as well as theScottish Government,[9] and theUnited Nations usesSpecial Advisers. The US government uses both:Council of Economic Advisers,Office of the Legal Adviser,Deputy National Security Advisor (deputy to the President's NSA), Legal "Advisor" (Office for the Administrative Review of the Detention of Enemy Combatants), that was part of the team tasked to conduct Combatant Status Review Tribunals of captives detained in Guantanamo Bay, and lawsInvestment Advisers Act of 1940. TheBureau of Educational and Cultural Affairs'sFulbright Program has "advisers".
Use of "advisor" appeared in print in the United States in 1889, withThe Tennessee Justice and Legal Advisor by William C. Kain and Horace N. Hawkins.[10]The Department of Justice of the United States, Issue 15, printed in 1927 by the Institute For Government Research, uses both spellings: "1. Political adviser and assistant to the President" and "Legal Advisor. Like all the other cabinet officers, the Attorney General is a political advisor of the President".[11]
Examples of the use of adviser and advisor in the media on a particular subject:
| Portrait | Name | Year | Origin | Notes |
|---|---|---|---|---|
 | Chanakya | 375–283 BCE | India | Indian polymath and a royal advisor of Mauryan EmperorsChandragupta andBindusara who authored the ancient Indian political treatise, theArthashastra |
 | Birbal | 1528-1586 | Madhya Pradesh,India | Advisor and main commander (Mukhya Senapati) of army in the court of theMughal emperor,Akbar and one of theAkbar's Navratnas |
.jpg) | Bairam Khan | 1501-1561 | Badakhshan,Central Asia | At the court of theMughal Emperors,Humayun andAkbar |
 | Henry Kissinger | 1923-2023 | Weimar Republic,Germany | American diplomat, who served asUnited States Secretary of State andNational Security Advisor |
 | Yelu Chucai | 1190-1244 | Yanjing,Jin dynasty | Khitan adviser toGenghis Khan and his sonÖgedei |
