Definitions
American Heritage® Dictionary of the English Language, Fourth Edition
- n. A ringlike figure, part, structure, or marking, such as a growth ring on the scale of a fish.
- n. A ring or group of thick-walled cells around the sporangia of many ferns that functions in spore release.
- n. The ringlike remains of a broken partial veil, found around the stipes of certain mushrooms.
- n. Mathematics The figure bounded by and containing the area between two concentric circles.
Century Dictionary and Cyclopedia
- n. A ring-like space or area contained between the circumferences of two concentric circles.
- n. In anatomy, a ring-like part, opening, etc.: used in Latin phrases.
- n. (See below.) In botany: The elastic ring which surrounds the spore-case of most ferns.
- n. In mosses, an elastic ring of cells lying between the lid and the base of the peristome or orifice of the capsule.
- n. In fungi, the slender membrane surrounding the stem in some agarics after the cap has expanded.
- n. In zoology: A thin chitinous ring which encircles the mantle in the Tetrabranchiata, connecting chitinous patches of the mantle into which the shell-muscles are inserted.
- n. In entomology, a narrow encircling band, generally of color; sometimes a raised ring.
- n. In astronomy, the ring of light seen about the edge of the moon in an annular eclipse of the sun. See annular eclipse, under annular.
- n. In the Equisetaceæ, the sheath below the spike formed by the union of the bases of the leaves.
- n. In diatoms, the rim of silex formed within the frustules of some genera.
- n. The fleshy rim of the corolla in milkweeds.
- n. One of the external subdivisions of the body of a leech, resembling a segment of the body of an earthworm. A single annulus, however, does not correspond to an internal segment. From 3 to 5 or even 12 annuli correspond to a segment in different genera.
Wiktionary
- n. A ring- or donut-shaped area or structure.
- n. geometry The region in a plane between two concentric circles of different radius.
- n. topology Any topological space homeomorphic to the region in a plane between two concentric circles of different radius.
- n. astronomy The ring of the sun not covered by the moon in an annular solar eclipse.
- n. botany Structure in a fern that consists of differentially thick-walled cells on a sporangium that bend and distort as a result of drying.
- n. mycology The membranous remnants of a partial veil which leaves a ring on the stem of a mushroom.
- n. oil and gas production The space contained between the centre well bore and any external tubing. Sometimes used for separated gas flow.
GNU Webster's 1913
- n. A ring; a ringlike part or space.
- n. A space contained between the circumferences of two circles, one within the other.
- n. The solid formed by a circle revolving around a line which is the plane of the circle but does not cut it.
- n. (Zoöl.) Ring-shaped structures or markings, found in, or upon, various animals.
WordNet 3.0
- n. a toroidal shape
- n. (Fungi) a remnant of the partial veil that in mature mushrooms surrounds the stem like a collar
Etymologies
- Latin ānulus, ring, diminutive of ānus. (American Heritage® Dictionary of the English Language, Fourth Edition)
Examples
“One of the biggest variables is whether the area called the annulus, which is between the inner piping and the outer casing, has sprung an oil leak.”
“One of the biggest variables on the static kill's finality is whether the area called the annulus, which is between the inner piping and the outer casing, has sprung an oil leak.”
CBS 4 - South Florida's Source for Breaking News, Weather, and Sports
“BP Senior Vice President Kent Wells said it's "really a possibility" that cement that engineers pumped in through the top went down into the reservoir, came back up and plugged the annulus, which is between the inner piping and the outer casing.”
The Washington Post: Storms delay completion of relief well to seal damaged BP oil well in gulf
“U.S. officials are concerned that the flooding of that area, known as the annulus, could compromise a cement plug that the company installed in early August at the top of the well.”
The Wall Street Journal: Weather Delays Progress at Well Site
“No one is sure if the oil and gas are flowing inside the pipe or outside the casing in what is called the annulus -- the space between the pipe and the rock wall of the hole.”
The Washington Post: BP aims to plug gulf oil well for good with two-pronged 'kill' shot
“U.S. officials were concerned that the injection of liquid into the gap between the well and the rock known as the annulus could compromise a cement plug that BP cast at the top of the well in early August, letting some oil escape into the ocean.”
The Wall Street Journal: BP to Push Ahead on Replacing Blowout Preventer
“There is one scenario, not considered likely, in which hydrocarbons would be lurking in the space known as the annulus, between the casing and the rock wall of the well bore, said retired Coast Guard Adm. Thad Allen, the national incident commander.”
The Washington Post: BP to test oil well for hydrocarbons during break in drilling relief well
“The former constitutes, according to Sir John Herschel's views, an annulus, that is to say, an independent zone, somewhat remote from our lenticular-shaped starry stratum, and similar to Saturn's ring.”
COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1
“BP Senior Vice President Kent Wells said it's "really a possibility" that cement engineers pumped in through the top went down into the reservoir, came back up and plugged the annulus, which is between the inner piping and the outer casing.”
“Teams first will drill into the outermost wall of the Macondo wellbore, known as the annulus, that encircles the round steel casing at the center of the well.”
Lists
These user-created lists contain the word ‘annulus’.
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Interesting words
A list of words that are odd or words that I have looked up.
concupiscence, brize, scree, scoria, forestaff, spanaemia, valetudinarianism, distasture, pyrethrum, laudanum, gentian, bicameral and 11184 more...
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Mycology
basidiomycete, initiation, fungus, shiitake, inoculum, substrate, fruit body, mycelium, hyphal growth, oyster, spawn run, polypore and 207 more...
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A Galimafrée of Plant Anatomy & Morph...
A hodgepodge, jumble, jambalaya, *gallimaufry, circus and tent revival of plant anatomy and morphology terms and phrases - its a big tent, and no tickets are required.
*array, collecti...naked bud, leaf blade, brochidodromous, serrate, cork cambium, rhizomatous, flower stalk, deciduous sepal, petal, whorl, nectar gland, stamen and 1348 more...
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Palynology
List of terms used in the study and classification of pollen and spores - both fossil and modern.
tetrad, abporal, ectoaperture, lacuna, grain, spore, lophate, acalymmate, monad, polyad, hexad, calymmate and 513 more...
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Latinate
lorem ipsum, citius, altius, fortius, curriculum vitae, bona fide, terra nullius, habeas corpus, quidnunc, voir dire, emeritus, quincunx and 99 more...
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ElRojo
R. Peter Jackson's list
cantillation, jackstaff, pullulate, whoremonger, colloquy, batman, anathema, idiosyncratic, facilitation, sympathy, empathy, satrap and 135 more...
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Not Quite As Awful As They Sound
masticate, absquatulate, adumbrate, afflatus, fetial, anile, bilabial, cineaste, smew, copse, piebald, testudinate and 156 more...
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sionnach's Words
contumely, fomite, holmgang, poltroon, eleemosynary, obsidian, nugatory, grindcore, felch, recrudescent, pyx, parenteral and 3271 more...
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Words of the Times
Words discovered while reading The New York Times, each with a citation from the paper.
testilying, ghost talk, apneist, solastalgia, izakaya, hooker, telectroscope, airflyte, phomance, bromhidrosis, stinky feet, cupping and 482 more...
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A
abligurition, acrid, Apollonian, apparatchik, appellation, atrabilious, Ave, Imperator, m..., absquatulate, abstemious, acedia, adduce, adjure and 61 more...
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Cool Shroomy Words
axenic, ascomycetes, shroud, zonate, mycelium, mycorrhiza, stroma, sclerotium, saprophyte, umbonate, psylocybin, lamellae and 3 more...
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perhapsolutely's Words
polyradiculoneuro..., abulia, abubble, abscission, abaft, zareba, abatis, abigail, abiogenesis, ablate, ablaut, abo and 1705 more...
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nimble wimble
hole wholes AND/OR headlight or lighthead
wimble, nimble, aureole, glory, annulus, corona, haloing, surrounding, surrealround, anthelion, gloriole, sundog and 16 more...
Tweets
Looking for tweets for annulus.

reesetee My thoughts exactly. Aug 5, 2010
chained_bear This word, to me at least, is disconcerting in its vague seaminess. Aug 4, 2010
john “If it only fills the center well pipe, and not the area called the annulus between the inner piping and the outer casing, then a final cementing of the well may have to wait another few weeks.”
The New York Times, BP Begins ‘Static Kill,’ to Seal Well Permanently, by Cliffor Klaus, August 3, 2010 Aug 4, 2010
bilby "Victoria hurried to the door. She arrived and stared down at the doorknob, apparently perplexed. Langdon arrived behind her and eyed the peculiar donut-shaped hoop hanging where the doorknob should have been.
'An annulus,' he whispered. Langdon reached out and quietly lifted the ring in his hand. He pulled the ring toward him. The fixture clicked."
- 'Angels and Demons', Dan Brown. Feb 28, 2008