A quality of a geometric figure that has exactly similar parts with respect
to a point, a line, or a plane of its own.
A geometric transformation that does not alter neither the shape nor the size of
a figure.
A property of a mathematical function whose value does not change when its variables
are interchanged.
Of physical phenomena, the property of remaining invariant under certain changes
(as of rotation, reflection, inversion in space, the sign of the electric charge,
parity, or the direction of time flow). See also
→ Noether’s theorem.
See also:
→ asymmetry,
→ axial symmetry,
→ axisymmetry,
→ baryon asymmetry,
→ charge-parity symmetry,
→ dissymmetry,
→ gauge symmetry,
→ parity symmetry,
→ spherical symmetry,
→ spontaneous symmetry breaking,
→ supersymmetry,
→ symmetry group,
→ T-symmetry.
Etymology (EN): From L. symmetria, from Gk. symmetria “agreement in dimensions,
due proportion, arrangement,” from symmetros “having a common
measure, even, proportionate,” from → syn- “together”
- metron “meter;” PIE base *me- “to measure;” cf. O.Pers., Av. mā-
“to measure;” Skt. mati “measures;” L. metri “to measure.”
Etymology (PE): Hamâmun from ham-, → syn- “together,” +
-â- epenthetic vowel + mun, variant mân “measure,” as in Pers. terms
pirâmun “perimeter,” âzmun “test, trial,”
peymân “measuring, agreement,” peymâné “a measure; a cup, bowl,”
from O.Pers./Av. mā(y)- “to measure;” cf.
Skt. mati “measures,” matra- “measure;” Gk. metron “measure;”
L. metrum; PIE base *me- “to measure.”
