annulus

annulus

English

Etymology

Borrowed from Latin annulus.

Pronunciation

• IPA^(key): /ˈænjʊləs/

Noun

annulus (plural annuluses or annuli)

1. A ring- or donut-shaped area or structure.
2. (geometry) The region in a plane between two concentric circles of different radii.
3. (topology) Any topological space homeomorphic to the region in a plane between two concentric circles of different radius.
4. (astronomy) The ring of the sun not covered by the moon in an annular solar eclipse.
5. (botany) Structure in a fern that consists of differentially thick-walled cells on a sporangium that bend and distort as a result of drying.
6. (mycology) The membranous remnants of a partial veil which leaves a ring on the stem of a mushroom.
7. (oil and gas production) The space contained between the centre well bore and any external tubing. Sometimes used for separated gas flow.

Synonyms

• (topological space): cylinder

Hyponyms

• (ring-shaped structure): torus

Derived terms

• annulus fibrosus
• annulus of Zinn
• apical annulus
• attached annulus
• double annulus
• single annulus
• square annulus

 

Related terms

• annular
• annulate
• annulation

Translations

ring-shaped structure

Aragonese: aniello m Asturian: aniellu m Catalan: anell (ca) m Corsican: anellu m Finnish: kehä (fi), rinkilä French: anneau (fr) m Galician: anel (gl) m German: Ring (de) m Irish: annalas m, fáinne (ga) m Italian: anello (it) m Latin: anulus m Portuguese: anel (pt) m Romanian: inel (ro) n Russian: кольцо́ (ru) n (kolʹcó), коле́чко (ru) n (koléčko) (small) Spanish: anillo (es) m

geometry: the region in a plane between two concentric circles of different radius

Finnish: rengasalue, annulus (fi) Hungarian: körgyűrű Romanian: coroană de cerc f, coroană circulară f Russian: кольцо́ (ru) n (kolʹcó) Slovene: kolobar m Spanish: corona circular f

astronomy: the ring of the sun not covered by the moon

Navajo: ahééjiichįįʼ Romanian: coroană solară (ro) f Spanish: corona solar f

botany: structure in a fern

Hungarian: annulusz

mycology: membranous remnants

Catalan: anell (ca) m Spanish: anillo (es) m

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Latin

Etymology

From ānus (“ring”) +‎ -ulus.

Pronunciation

• (Classical) IPA^(key): /ˈaːn.nu.lus/, [ˈäːnːʊɫ̪ʊs̠]
• (Ecclesiastical) IPA^(key): /ˈan.nu.lus/, [ˈänːulus]

Noun

ānnulus m (genitive ānnulī); second declension

1. Alternative form of ānulus

Declension

Second-declension noun.

Case	Singular	Plural
Nominative	ānnulus	ānnulī
Genitive	ānnulī	ānnulōrum
Dative	ānnulō	ānnulīs
Accusative	ānnulum	ānnulōs
Ablative	ānnulō	ānnulīs
Vocative	ānnule	ānnulī

Descendants

• English: annulus, annulet

References

• annulus in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
• “annulus”, in Harry Thurston Peck, editor (1898) Harper's Dictionary of Classical Antiquities, New York: Harper & Brothers
• “annulus”, in William Smith et al., editor (1890) A Dictionary of Greek and Roman Antiquities, London: William Wayte. G. E. Marindin