What is "symmetry"

Symmetry \Sym"me*try\, n. [L. symmetria, Gr. ?; sy`n with, together + ? a measure: cf. F. sym['e]trie. See Syn-, and Meter rhythm.]

1. A due proportion of the several parts of a body to each other; adaptation of the form or dimensions of the several parts of a thing to each other; the union and conformity of the members of a work to the whole.

2. (Biol.) The law of likeness; similarity of structure; regularity in form and arrangement; orderly and similar distribution of parts, such that an animal may be divided into parts which are structurally symmetrical.

   Note: Bilateral symmetry, or two-sidedness, in vertebrates, etc., is that in which the body can be divided into symmetrical halves by a vertical plane passing through the middle; radial symmetry, as in echinoderms, is that in which the individual parts are arranged symmetrically around a central axis; serial symmetry, or zonal symmetry, as in earthworms, is that in which the segments or metameres of the body are disposed in a zonal manner one after the other in a longitudinal axis. This last is sometimes called metamerism.

3. (Bot.)

   1. Equality in the number of parts of the successive circles in a flower.

   2. Likeness in the form and size of floral organs of the same kind; regularity.

      Axis of symmetry. (Geom.) See under Axis.

      Respective symmetry, that disposition of parts in which only the opposite sides are equal to each other.

1560s, "relation of parts, proportion," from Middle French symmétrie (16c.) and directly from Latin symmetria, from Greek symmetria "agreement in dimensions, due proportion, arrangement," from symmetros "having a common measure, even, proportionate," from assimilated form of syn- "together" (see syn-) + metron "meter" (see meter (n.2)). Meaning "harmonic arrangement of parts" first recorded 1590s.

n. 1 Exact correspondence on either side of a dividing line, plane, center or axis. 2 (context uncountable English) The satisfying arrangement of a balanced distribution of the elements of a whole.

1. n. (mathematics) an attribute of a shape or relation; exact correspondence of form on opposite sides of a dividing line or plane [syn: symmetricalness, correspondence, balance] [ant: asymmetry]

2. balance among the parts of something [syn: proportion] [ant: disproportion]

3. (physics) the property of being isotropic; having the same value when measured in different directions [syn: isotropy] [ant: anisotropy]

"Symmetry" is a song by Australian recording artist Gabriella Cilmi. It was released as the second single from her third studio album The Sting on 11 November 2013 on digital download format.

A music video was released on 17 September, it was directed by Tim Fox, the director of o Saris' 'The Addict' and Zico Chain's 'New Romantic'. The video features Cilmi and a long-haired actor in a space other-worldly atmosphere that reminds us of her Ten lead single On a Mission.

Symmetry is a 2003 Polish drama film directed by Konrad Niewolski.

Symmetry (from Greek συμμετρία symmetria "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definition, that an object is invariant to any of various transformations; including reflection, rotation or scaling. Although these two meanings of "symmetry" can sometimes be told apart, they are related, so they are here discussed together.

Mathematical symmetry may be observed with respect to the passage of time; as a spatial relationship; through geometric transformations; through other kinds of functional transformations; and as an aspect of abstract objects, theoretic models, language, music and even knowledge itself.

This article describes symmetry from three perspectives: in mathematics, including geometry, the most familiar type of symmetry for many people; in science and nature; and in the arts, covering architecture, art and music.

The opposite of symmetry is asymmetry.

In physics, a symmetry of a physical system is a physical or mathematical feature of the system (observed or intrinsic) that is preserved or remains unchanged under some transformation.

A family of particular transformations may be continuous (such as rotation of a circle) or discrete (e.g., reflection of a bilaterally symmetric figure, or rotation of a regular polygon). Continuous and discrete transformations give rise to corresponding types of symmetries. Continuous symmetries can be described by Lie groups while discrete symmetries are described by finite groups (see Symmetry group).

These two concepts, Lie and finite groups, are the foundation for the fundamental theories of modern physics. Symmetries are frequently amenable to mathematical formulations such as group representations and can, in addition, be exploited to simplify many problems.

Arguably the most important example of a symmetry in physics is that the speed of light has the same value in all frames of reference, which is known in mathematical terms as Poincaré group, the symmetry group of special relativity. Another important example is the invariance of the form of physical laws under arbitrary differentiable coordinate transformations, which is an important idea in general relativity.

Symmetry may refer to:

In science and mathematics:

• Symmetry (physics), a physical or mathematical feature of the system (observed or intrinsic) that is "preserved" under some change
• Symmetry in biology, the balanced distribution of duplicate body parts or shapes
• Symmetry in chemistry, i.e., in the chirality or symmetry of molecules
• Symmetry in mathematics, occurs not only in geometry, but also in other branches of mathematics
• Symmetry, a line of SMP computers by Sequent Computer Systems
• Symmetry Magazine, a Fermilab/ SLAC publication covering advanced physics

In arts and entertainment:

• Symmetry (band), American instrumental duo
• Symmetry (film), a Polish film
• "Symmetry" (Dead Zone), an episode of the television series Dead Zone
• Symmetric scale, in music
• "Symmetry", a song by Little Boots on the album Hands

Other uses:

• Facial symmetry, a component of attractiveness
• "Symmetry", street name of salvinorin B ethoxymethyl ether, a dissociative drug

Symmetry (foaled 1795) was a British Thoroughbred racehorse and sire best known for winning the classic St Leger Stakes in 1798. Originally trained in Yorkshire won the St Leger at Donacaster on his final appearance as a three-year-old and when on to defeat the Epsom Derby winner Sir Harry in a match race at York in the following year. As a five-year-old he was transferred to race at Newmarket where he lost a rematch with Sir Harry, but won his three remaining races, including matches against Sorcerer and Diamond, two of the leading racehorss of the time. After his retirement from racing, Symmetry was sold and exported to stand as a breeding stallion in Russia.

Symmetry is an American instrumental musical duo consisting of Johnny Jewel and Nat Walker of Chromatics.

In late 2010 Jewel was asked by director Nicolas Winding Refn and lead actor Ryan Gosling to score the film Drive. He collaborated with Walker, but their material was ultimately not used. However the film soundtrack did include previously released music from Chromatics and Desire, both on Jewel's Italians Do It Better label. Jewel and Walker then formed Symmetry and further reworked and expanded on the original tracks, ending up with nine hours of music, two hours of which were released as an LP entitled "Themes For An Imaginary Film" in 2011. In 2011, they also released a limited run promotional LP entitled The Messenger, limited edition of 1500 copies on clear vinyl. In October 2013, a video for the song "The Hunt" was also released via YouTube.

Symmetry has performed live internationally at private events for a number of fashion lines, including Gucci and Chanel.

Their song "The Hunt" is used as the main theme song to the American television series "Those Who Kill" on A&E.

On February 3, 2015, Symmetry released their remix of the Chromatics track "Yes (Love Theme To Lost River)", the trailer music to Ryan Gosling's directorial debut, Lost River. Symmetry's Remix of "Yes" was used as trailer music for the Lost River film in Spain.

A geometric object has symmetry if there is an "operation" or "transformation" (technically, an isometry or affine map) that maps the figure/object onto itself; i.e., it is said that the object has an invariance under the transform. For instance, a circle rotated about its center will have the same shape and size as the original circle—all points before and after the transform would be indistinguishable. A circle is said to be symmetric under rotation or to have rotational symmetry. If the isometry is the reflection of a plane figure, the figure is said to have reflectional symmetry or line symmetry; moreover, it is possible for a figure/object to have more than one line of symmetry.

The types of symmetries that are possible for a geometric object depend on the set of geometric transforms available, and on what object properties should remain unchanged after a transform. Because the composition of two transforms is also a transform and every transform has an inverse transform that undoes it, the set of transforms under which an object is symmetric form a mathematical group.