n. 1
Oneness: the state or fact of being one undivided entity.
Near-synonyms: unification, unionization, integration
n. 2
Agreement; harmony.
n. 3
A single undivided thing, seen as complete in itself.

Related words

Word family: unique unison unitisation
Phrases: classical unity dramatic unity

Forms

Plural: unities → onenesses, unions, harmonies, unifications…

Choose the right word

Unity or Oneness?

Unity is oneness, the state of being one, especially of that which never has been divided or of that which can not be conceived of as resolved into parts; as, the unity of God or the unity of the human soul.

J. C. Fernald, English Synonyms and Antonyms (1914)

Example sentences

union It is improper to impose sanctions upon the union.
harmony He seems to live in harmony with all his friends.
unification Berlin is a symbol of unification between the East and the West.
oneness The oneness of God is the most central tenet in Islam.
togetherness Ziri and Rima cried, remembering their togetherness again.

Popularity over time

Word	1850 → 2019	Trend
unity		falling
union		falling
harmony		steady
unification		steady
oneness		rising

Use in printed books, per decade from 1850 to 2019.

By length

3 letters: one¹, ace¹
4 letters: unit²
5 letters: union²
6 letters: single², unison³
7 letters: harmony³, concord², oneness², unicity
8 letters: identity⁴, junction²
9 letters: community⁴, agreement³, integrity⁴, communion³, wholeness², unanimity⁵
10 letters: uniformity⁵, singleness, unitedness
11 letters: integration⁴, unification⁵
12 letters: togetherness⁴, unionization⁵, unionisation
13 letters: individuality⁷
14 letters: indivisibility

The small number after each word is its number of syllables (unit² = 2 syllables).