annulus
Language: English
Part of speech: noun
Pronunciation: ipa: /ˈænjʊləs/
ipa: /ˈænjələs/
ipa: /ˈænjʊlaɪ/
ipa: /-li/
ipa: /ˈænjəlaɪ/
ipa: /-li/
Forms: form: annuluses
form: annuli
Etymology: Learned borrowing from Medieval Latin ānnulus, a misspelling of Latin ānulus (“ring, especially one worn on a finger”), from ānus (“ring”) (possibly from Proto-Indo-European *h₁eh₂-n-o- (“ring”), from an uncertain root) + -ulus (diminutive suffix).
The plural form annuli is a learned borrowing from Medieval Latin ānnulī.
Senses: examples: text: But by the knots I am ſpeaking of, may it pleaſe your reverences to believe, that I mean good, honeſt, deviliſh tight, hard knots, made bona fide, as Obadiah made his;—in vvhich there is no quibbling proviſion made by the duplication and return of the tvvo ends of the ſtrings through the annulus or nooſe made by the ſecond implication of them— […]
ref: 1761, [Laurence Sterne], chapter IX, in The Life and Opinions of Tristram Shandy, Gentleman, volume III, London: […] R[obert] and J[ames] Dodsley […], →OCLC, pages 29–30:
hyponyms: torus
glosses: A ring- or donut-shaped area, object, or structure.
topics: anatomy
medicine
sciences
glosses: A ring of fibrous tissue; specifically (cardiology), such a ring around an opening of a heart valve, to which the valve leaflets and muscle fibres of the atria and ventricles are attached; an annulus fibrosus cordis.
topics: astronomy
natural-sciences
glosses: A ring of light in a celestial body, especially when caused by an annular eclipse (for example, when the Sun and Moon are in line with the Earth, but the Moon does not completely cover the Sun's disc).
topics: biology
botany
natural-sciences
glosses: A structure surrounding a sporangium (or part of it) which shrinks and causes it to rupture for spore dispersal; specifically, in a fern: a structure around about two-thirds of the sporangium consisting of differentially thick-walled cells which dry and distort the sporangium; and in a moss: a complete ring of cells around the tip of the sporangium which dissolves to cause the tip to detach.
topics: biology
mycology
natural-sciences
glosses: The membranous remnants of a partial veil which leaves a ring on the stem of a mushroom.
topics: biology
ichthyology
natural-sciences
zoology
coordinate_terms: circulus
focus
glosses: A dark ring on a fish's scale that is formed when a fish's growth rate slows down in the winter due to low food intake and the scale's circuli move closer to one another. The dark ring is used to estimate the fish's age, approximately one year per annulus.
topics: geometry
mathematics
sciences
glosses: The region in a plane between two concentric circles of different radii.
topics: mathematics
sciences
topology
synonyms: cylinder
glosses: Any topological space homeomorphic to the region in a plane between two concentric circles of different radii.
examples: text: Pressure balance is obtained by the air pressure in the cylinder operating on a supplementary piston in the buffer piston head, transmitting pressure to a small quantity of oil which is ported to an annulus between the buffer piston seals and the cylinder wall, so that the seal is always under opposing pressures; oil on one side and air on the other.
ref: 1950 September, “Notes and News: Pneumatic Buffer Stop, E.R.”, in The Railway Magazine, London: Tothill Press, →ISSN, →OCLC, page 642:
topics: engineering
natural-sciences
physical-sciences
technology
glosses: In a well such as an oil well or water well: the space between a pipe or tube and any pipe, tube, casing, or sides of a hole surrounding it.
Derived terms: annulotomy
annulus fibrosus
annulus of Zinn
apical annulus
attached annulus
double annulus
periannulus
single annulus
square annulus
Related terms: word: annular
word: annularity
word: annularly
word: annulary
word: annulate
word: annulated
word: annulation
word: annule
word: annulet
word: exannulate
word: mitral annulus
word: quadriannulate
word: sexannulate
word: triannulate
word: triannulated