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

(identities)

Sameness, identicalness; the quality or fact of (several specified things) being the same.

* 1997 , Hydrothermal Vent Fauna'', in ''Advances in Marine Biology: The Biogeography of the Oceans , page 111:

The difference or character that marks off an individual from the rest of the same kind, selfhood.

*

A name or persona—the mask or appearance one presents to the world—by which one is known.

This criminal has taken on several identities .

Sense of who one is.

I've been through so many changes, I have no sense of identity .

This nation has a strong identity .

(algebra, computing) Any function which maps all elements of its domain to themselves.

(algebra) An element of an algebraic structure which, when applied to another element under an operation in that structure, yields this, second element.