Definition of univalent in US English:



  • 1Biology
    (of a chromosome) remaining unpaired during meiosis.

    • ‘Twelve univalent chromosomes are visible in this diakinesis-stage nucleus, indicating an absence of chiasmata.’
    • ‘Neither fold backs and pairing partner switches characteristic of nonhomologous synapsis nor univalent chromosomes were observed, although some short regions at distal ends of chromosomes could be unsynapsed (image not shown).’
    • ‘Mutants in all three meiotic genes display diakinesis oocytes containing 12 individual DAPI - stained bodies corresponding to achiasmate univalent chromosomes.’
    • ‘To ask which general class of events might be affected, we examined the transmission of univalent chromosomes.’
    • ‘For his doctorate he was using contour integration to study different problems concerning functions which are univalent in a domain of finite connectivity.’
  • 2Chemistry

    another term for monovalent
    • ‘This latter explanation fits with ionic current data that have shown that C-type inactivation is accelerated when the extracellular cation concentration is changed or univalent metal cations are removed altogether.’
    • ‘The complications arising from quadrivalent or trivalent plus univalent formation are not considered in this article.’
    • ‘In our experiments we deal with a system consisting of polycations and macroanions, as well as univalent counterions.’
    • ‘Formation of ROS occurs through several univalent reduction steps, yielding first the superoxide anion, then hydrogen peroxide and the hydroxyl radical, and finally water.’


  • A univalent chromosome.

    • ‘All alien chromosomes behaved as univalents during meiosis.’
    • ‘Chromosome configurations at metaphase I of two triploids and two aneuploids were comprised of univalents, bivalents, and trivalents.’
    • ‘Maize hybrids with a type of teosinte from Guatemala, known as Florida teosinte, were partially sterile, exhibited incomplete chromosomal homology, produced some univalents, and had reduced linkage distances.’
    • ‘Their nuclei contain univalents as well as bivalents at diakinesis and metaphase I.’
    • ‘Since individual univalents or bivalents in some nuclei may lie too close to each other to be resolved unambiguously, this method underestimates the frequency of achiasmate chromosomes.’