\U"ni*ty\, n.; pl. {Unities}. [OE. unite, F. unit['e], L.
unitas, from unus one. See {One}, and cf. {Unit}.]
1. The state of being one; oneness.
         Whatever we can consider as one thing suggests to
         the understanding the idea of unity.  --Locks.
Note: Unity is affirmed of a simple substance or indivisible
      monad, or of several particles or parts so intimately
      and closely united as to constitute a separate body or
      thing. See the Synonyms under {Union}.
2. Concord; harmony; conjunction; agreement; uniformity; as,
   a unity of proofs; unity of doctrine.
         Behold, how good and how pleasant it is for brethren
         to dwell together in unity!           --Ps. cxxxiii.
                                               1.
3. (Math.) Any definite quantity, or aggregate of quantities
   or magnitudes taken as one, or for which 1 is made to
   stand in calculation; thus, in a table of natural sines,
   the radius of the circle is regarded as unity.
Note: The number 1, when it is not applied to any particular
      thing, is generally called unity.
4. (Poetry & Rhet.) In dramatic composition, one of the
   principles by which a uniform tenor of story and propriety
   of representation are preserved; conformity in a
   composition to these; in oratory, discourse, etc., the due
   subordination and reference of every part to the
   development of the leading idea or the eastablishment of
   the main proposition.
Note: In the Greek drama, the three unities required were
      those of action, of time, and of place; that is, that
      there should be but one main plot; that the time
      supposed should not exceed twenty-four hours; and that
      the place of the action before the spectators should be
      one and the same throughout the piece.
5. (Fine Arts & Mus.) Such a combination of parts as to
   constitute a whole, or a kind of symmetry of style and
   character.
6. (Law) The peculiar characteristics of an estate held by
   several in joint tenancy.
Note: The properties of it are derived from its unity, which
      is fourfold; unity of interest, unity of title, unity
      of time, and unity of possession; in other words, joint
      tenants have one and the same interest, accruing by one
      and the same conveyance, commencing at the same time,
      and held by one and the same undivided possession.
      Unity of possession is also a joint possession of two
      rights in the same thing by several titles, as when a
      man, having a lease of land, afterward buys the fee
      simple, or, having an easement in the land of another,
      buys the servient estate.
{At unity}, at one.
{Unity of type}. (Biol.) See under {Type}.
Syn: Union; oneness; junction; concord; harmony. See {Union}.