Definition of annulus in English:


nounplural noun annuli/-ˌlī/

  • A ring-shaped object, structure, or region.

    ‘Channel incorporation was typically achieved within a few minutes after ‘brushing’ the membrane fraction across the annulus with fresh lipids to form a new bilayer.’
    • ‘The tympanic annulus must be completely visible.’
    • ‘The fibrillar collagens also change across the disc, with the nucleus containing only type II collagen while both types I and type II are found in the annulus.’
    • ‘The position of the annulus is a key character used to differentiate lineages within the clade.’
    • ‘The calcification extended into the mitral annulus.’
    • ‘It is possible that the ligamenta flava provide some resistance to flexion and so, like the posterior longitudinal ligament, protect the posterior annulus.’
    • ‘Many derived mosses have yet another control on spore dispersal: a peristome with peristome teeth arranged around an annulus.’
    • ‘Within this recess we would find the curved remnants of the angular (the tympanic) which actually form the tympanic annulus.’
    • ‘The structure of the annulus provides stability, and the elastic nature of the nucleus allows it to change shape to distribute forces equally along the cervical spine.’
    • ‘A beamsplitter mixes the returning measurement beam with the collimated local beam; the inner core component is directed to the target detector and the outer annulus goes to the reference detector.’
    • ‘Mitral valve prolapse occurs when varying portions of one or both leaflets of the mitral valve extend or protrude abnormally above the mitral annulus into the left atrium.’
    • ‘No defect was detected in the relocation of the paired centrioles to abut the nuclear membrane or in the initial formation of the annulus.’
    • ‘Exploration of the right ear suggested a fistula in the anterior annulus of the oval window, with perilymphatic fluid leak visible on Valsalva at middle ear exploration.’
    • ‘The cells of the outer annulus are thin and extended along the collagen fibrils, rather like tendon cells.’
    • ‘The pipette microchamber introduces a mechanical constraint around the annulus where the pipette tip contacts the plasma membrane.’
    • ‘At the other end, headgroups of phospholipids should form an annulus through which permeating ions must pass to cross the membrane.’
    • ‘The inner and outer margins of the annulus were observed to bulge outwards but when the nucleus was removed the inner margins bulged inwards.’
    • ‘The nucleus eventually no longer acts hydrostatically, thus the annulus and endplate are exposed to high point stresses which might lead to the cracks and fissures seen in degenerate discs.’
    • ‘Under these circumstances neither the annulus nor the lipid membrane will be situated symmetrically around the edges of the orifice.’
    • ‘At a lateral optical resolution of 0.4 m FWHM the bright fluorescence of the lipid annuli outshone the very weak fluorescence of the bilayer membranes.’



/ˈanyələs/ /ˈænjələs/


Mid 16th century from Latin anulus, annulus.