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

(en noun)

(countable) The act of uniting or joining two or more things into one.

(uncountable) The state of being united or joined.

(countable) That which is united, or made one; something formed by a combination or coalition of parts or members; a confederation; a consolidated body; a league.

(countable) A trade union; a workers' union.

* , chapter=22

, title= The Mirror and the Lamp , passage=In the autumn there was a row at some cement works about the unskilled labour men. A union had just been started for them and all but a few joined. One of these blacklegs was laid for by a picket and knocked out of time.}}

(countable) A joint or other connection uniting parts of machinery, such as pipes.

(countable, set theory) The set containing all of the elements of two or more sets.

(countable) The act or state of marriage.

(uncountable, archaic, euphemistic) Sexual intercourse.

(countable, computing) A data structure that can store any of various items, but only one at a time.

A large, high-quality pearl.

*, II.3.3:

Nonius the senator hath a purple coat as stiff with jewels as his mind is full of vices; rings on his fingers worth 20,000 sesterces, andan union in his ear worth an hundred pounds' weight of gold […].