Noun

(uncountable) Oneness; the state or fact of being one undivided entity.

* 1846 ,

If any literary work is too long to be read at one sitting, we must be content to dispense with the immensely important effect derivable from unity of impression - for, if two sittings be required, the affairs of the world interfere, and everything like totality is at once destroyed.

* {{quote-news

, year=2011 , date=October 1 , author=Saj Chowdhury , title=Wolverhampton 1 - 2 Newcastle , work=BBC Sport citation , page= , passage=Alan Pardew's current squad has been put together with a relatively low budget but the resolve and unity within the team is priceless.}}

A single undivided thing, seen as complete in itself.

* 1999 , Joyce Crick, translating Sigmund Freud, The Interpretation of Dreams , Oxford 2008, p. 137:

If a single day has brought us two or more experiences suitable to initiate a dream, the dream will unite references to them both into a single whole; it obeys a compulsion to form a unity out of them .

(drama) Any of the three classical rules of drama (unity of action, unity of place, and unity of time).`

(mathematics) Any element of a set or field that behaves under a given operation as the number 1 behaves under multiplication.

(legal) The peculiar characteristics of an estate held by several in joint tenancy.

Noun

(label) The power to enforce rules or give orders.

* 1883 , (Howard Pyle), (The Merry Adventures of Robin Hood)

But in the meantime Robin Hood and his band lived quietly in Sherwood Forest, without showing their faces abroad, for Robin knew that it would not be wise for him to be seen in the neighborhood of Nottingham, those in authority being very wroth with him.

(label) Persons in command; specifically, government.

*{{quote-book, year=1927, author= F. E. Penny

, chapter=4, title= Pulling the Strings , passage=The case was that of a murder. It had an element of mystery about it, however, which was puzzling the authorities . A turban and loincloth soaked in blood had been found; also a staff.}}

* {{quote-magazine, date=2013-08-10, volume=408, issue=8848, magazine=(The Economist)

, title= Legal highs: A new prescription , passage=No sooner has a [synthetic] drug been blacklisted than chemists adjust their recipe and start churning out a subtly different one. These “legal highs” are sold for the few months it takes the authorities to identify and ban them, and then the cycle begins again.}}

(label) A person accepted as a source of reliable information on a subject.

* 1930 September 18, Albert Einstein, as quoted in Albert Einstein: Creator and Rebel (1988) by Banesh Hoffman

To punish me for my contempt of authority', Fate has made me an ' authority myself.