asymmetry

n. lack of symmetry, lack of balance and proportion

Asymmetry is the absence of, or a violation of, a symmetry.
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Noun
1. (mathematics) a lack of symmetry
(synonym) imbalance
(antonym) symmetry, symmetricalness, correspondence, balance
(hypernym) spatial property, spatiality
(hyponym) irregularity, geometrical irregularity
(classification) mathematics, math, maths

(n.)
Want of symmetry, or proportion between the parts of a thing, esp. want of bilateral symmetry.
  

(n.)
Incommensurability.
  

noun
state where two sides of the body, of an organ are not closely similar to each other