Emir is a title of high office, used throughout the Muslim world

Muslim world

The term Muslim world has several meanings. In a religious sense, it refers to those who adhere to the teachings of Islam, referred to as Muslims. In a cultural sense, it refers to Islamic civilization, inclusive of non-Muslims living in that civilization...

. Emirs are usually considered high-ranking Sheikh

Sheikh

Not to be confused with sikhSheikh — also spelled Sheik or Shaikh, or transliterated as Shaykh — is an honorific in the Arabic language that literally means "elder" and carries the meaning "leader and/or governor"...

s, but in monarchic states the term is also used for Prince

Prince

Prince is a general term for a ruler, monarch or member of a monarch's or former monarch's family, and is a hereditary title in the nobility of some European states. The feminine equivalent is a princess...

s, with "Emirate

Emirate

An emirate is a political territory that is ruled by a dynastic Muslim monarch styled emir.-Etymology:Etymologically emirate or amirate is the quality, dignity, office or territorial competence of any emir ....

" being analogous to a principality

Principality

A principality is a monarchical feudatory or sovereign state, ruled or reigned over by a monarch with the title of prince or princess, or by a monarch with another title within the generic use of the term prince....

.

While Emir is a common transliteration in English and other languages, the form Amir is found for numerous compounds (e.g. admiral

Admiral

Admiral is the rank, or part of the name of the ranks, of the highest naval officers. It is usually considered a full admiral and above vice admiral and below admiral of the fleet . It is usually abbreviated to "Adm" or "ADM"...

) and names. Transliteration differs depending on the sources consulted.
Amir, meaning "chieftain" or "commander", is derived from the Arabic root , "command".