Meaning of quaternary in English:


Pronunciation /kwəˈtəːn(ə)ri/


  • 1Fourth in order or rank; belonging to the fourth order.

    ‘In the more complicated previous model [3-6], higher total R1 concentrations favor higher order quaternary states.’
    • ‘The fitting procedure shows that only the quaternary model built using the as a template, and modified to accommodate only one zinc ion in the catalytic site (Model B), agrees with the experimental data.’
    • ‘One of the two vascular hemoglobins possesses a hexagonal-bilayer hemoglobin (HBL-Hb) quaternary structure, which is only found in the Annelida and Vestimentifera.’
  • 2

    (also Quaternary)
    Relating to or denoting the most recent period in the Cenozoic era, following the Tertiary period and comprising the Pleistocene and Holocene epochs.

    ‘Together, the Pleistocene and Holocene make up the Quaternary period, marked by waxing and waning of polar glaciers.’
    • ‘In the southern part of the valley, the Serghaya Fault Zone follows the mountain front juxtaposing recent alluvium and colluvium against late Quaternary lake sediments, Neogene conglomerates, and Cretaceous carbonates.’
    • ‘Late Tertiary and Quaternary glacial, alluvial and lacustrine sediments are widespread adjacent to the mountains and in intermontane basins.’
    • ‘Hence, fundamental differences in the available datasets hinder an in-depth comparison of mid-Cretaceous with Pliocene to Quaternary black shale successions.’
    • ‘Miocene-Pliocene volcanic rocks have a calc-alkaline character which gives way to a predominantly alkaline character in late Pliocene to Quaternary times.’
  • 3Chemistry
    Denoting an ammonium compound containing a cation of the form NR₄⁺, where R represents organic groups or atoms other than hydrogen.

    ‘Chatburn and coworkers compared the effectiveness of two concentrations of acetic acid, quaternary ammonium compound, and household detergent against a mixture of P. aeruginosa, S. aureus, and Pseudomonas cepacia.’
    • ‘Phenols and phenolics, quaternary ammonium compounds, 1: 500 bleach - water solutions, and iodine and iodophors are used in low-level disinfection.’
    • ‘Their activity may be enhanced by using membrane-disrupting surfactants such as quaternary ammonium compounds.’
    • ‘Glycinebetaine (N, N, N-trimethylglycine; hereafter betaine) is a quaternary ammonium compound that occurs naturally in a wide variety of plants, animals and microorganisms.’
    • ‘Studies of multidrug-resistant proteins have demonstrated two types of residues involved in binding to quaternary ammonium compounds.’
    1. 3.1(of a carbon atom) bonded to four other carbon atoms.
      ‘What remains to be determined is how the reaction mechanism for this enzyme might differ from those PBGS that show both an absolute requirement for metal ions and an octameric quaternary structure.’
      • ‘The inherent positive charge of the quaternary nitrogen and hydrophobic retinoid side chains in A2E suggest that it may behave as a surfactant.’
      • ‘The quaternary nitrogen atom in lycobetaine plays an important role in the formation of hydrogen bonds between the compound and the oligonucleotide.’
      • ‘Because this enzyme shows no activity in its monomeric form, correct quaternary structure is essential for the formation of active enzyme.’
      • ‘Calsequestrin, the major calcium sequestering protein in the sarcoplasmic reticulum of muscle, forms a quaternary complex with the ryanodine receptor calcium release channel and the intrinsic membrane proteins triadin and junctin.’


  • the QuaternaryThe Quaternary period or the system of deposits laid down during it.

The Quaternary began about 1,640,000 years ago and is still current. Humans and other mammals evolved into their present forms, and were strongly affected by the ice ages of the Pleistocene


Late Middle English (as a noun denoting a set of four): from Latin quaternarius, from quaterni ‘four at once’, from quater ‘four times’, from quattuor ‘four’.