What does dissymmetric mean?
Dissymmetric is a formal adjective meaning lacking symmetry — describing something whose corresponding parts do not match in size, shape, or arrangement. It is most at home in technical fields such as chemistry, crystallography, and physics, where it often describes molecules that are not superimposable on their mirror images, a property also known as chirality. A dissymmetric crystal or molecular structure may therefore exhibit distinctive behaviour, such as rotating polarized light. Beyond the laboratory, the word can be applied more loosely to any irregular or lopsided arrangement, though in everyday English the far more common choice is 'asymmetric'. Derived from Greek roots via French scientific usage — combining the negative prefix 'dis-' with 'symmetric', from Greek 'metron' meaning measure — the word carries a precise, scholarly connotation. Its noun form, dissymmetry, names the state of being unsymmetrical. Writers typically reach for it when they want exactness rather than the vaguer force of 'lopsided' or 'uneven'.
Lacking symmetry between corresponding parts; not symmetrical in form or arrangement.
"The dissymmetric layout of the garden reflected its organic, unplanned growth."
Especially common in scientific and mathematical writing.
(Chemistry) Of a molecule or object: not superimposable on its mirror image; chiral.
"A dissymmetric carbon centre gives rise to optical activity in the compound."
Often used interchangeably with 'chiral' in older chemical literature.
In chemistry, a dissymmetric molecule is one whose mirror image cannot be superimposed on itself — the same property that makes your left and right hands different.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of dissymmetric
Dissymmetric combines the prefix 'dis-', indicating negation or reversal, with 'symmetric', which derives from Greek 'symmetros' ('measured together') from 'metron' ('measure'). The word entered English scientific vocabulary in the nineteenth century, influenced by French usage such as Pasteur's work on dissymmetric crystals and molecular chirality. It shares its root with words like symmetry, meter, and diameter, all tracing back to the Greek notion of measurement.
Related word forms
How dissymmetric is actually used
Formal and largely technical in register; common in chemistry, crystallography, mathematics, and physics, where it is sometimes used interchangeably with 'chiral' or 'asymmetric'. In general prose, 'asymmetric' is far more frequent, so 'dissymmetric' can sound specialized or old-fashioned outside scientific writing.
Easily confused with dissymmetric
Both mean lacking symmetry, but 'dissymmetric' is rarer and often implies a specific imbalance or lack of mirror-image correspondence, whereas 'asymmetric' is the general everyday term.