• WordNet 3.6
    • n annulus (Fungi) a remnant of the partial veil that in mature mushrooms surrounds the stem like a collar
    • n annulus a toroidal shape "a ring of ships in the harbor","a halo of smoke"
    • ***
Webster's Revised Unabridged Dictionary
    • Annulus A ring; a ringlike part or space.
    • Annulus (Geom) A space contained between the circumferences of two circles, one within the other.
    • Annulus (Zoöl) Ring-shaped structures or markings, found in, or upon, various animals.
    • Annulus (Geom) The solid formed by a circle revolving around a line which is the plane of the circle but does not cut it.
    • ***
Century Dictionary and Cyclopedia
    • n annulus A ring-like space or area contained between the circumferences of two concentric circles.
    • n annulus In anatomy, a ring-like part, opening, etc.: used in Latin phrases.
    • n annulus (See below.) In botany: The elastic ring which surrounds the spore-case of most ferns.
    • n annulus In mosses, an elastic ring of cells lying between the lid and the base of the peristome or orifice of the capsule.
    • n annulus In fungi, the slender membrane surrounding the stem in some agarics after the cap has expanded.
    • n annulus 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 annulus In entomology, a narrow encircling band, generally of color; sometimes a raised ring.
    • n annulus 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 annulus In the Equisetaceæ, the sheath below the spike formed by the union of the bases of the leaves.
    • n annulus In diatoms, the rim of silex formed within the frustules of some genera.
    • n annulus The fleshy rim of the corolla in milkweeds.
    • n annulus 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.
    • ***


Webster's Revised Unabridged Dictionary


In literature:

That part of the veil which breaks away from the cap, called the secondary veil, forms the annulus or ring.
"Among the Mushrooms" by Ellen M. Dallas and Caroline A. Burgin
A distinct operculum is usually detached by the help of the annulus, and its removal may leave the mouth of the capsule widely open.
"Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3" by Various
Annulet: a small or narrow ring or annulus.
"Explanation of Terms Used in Entomology" by John. B. Smith
Resembling an annulus or ring.
"The Sailor's Word-Book" by William Henry Smyth
The =annulus= is thick, and the under side marked by loose threads or scales.
"Studies of American Fungi. Mushrooms, Edible, Poisonous, etc." by George Francis Atkinson
The annulus is frequently torn from the stem and is found adhering to the margin of the cap.
"The Mushroom, Edible and Otherwise" by M. E. Hard
It is the annular atmosphere of the aqueous annulus.
"The Plurality of Worlds" by William Whewell
Calculation of length at the last annulus for both scale-fish and catfish was made by direct proportion.
"Fishes of the Big Blue River Basin, Kansas" by W. L. Minckley
The annulus round the iris is pointed out as resembling a circle of the nine gems.
"The Atlantic Monthly, Volume 20, No. 120, October, 1867." by Various
What we have said of a straight liquid cylinder applies also to an annulus of liquid made by bending such a cylinder into a ring.
"A Study of Splashes" by Arthur Mason Worthington

In news:

Severe axial loading of the spine may produce end-plate disruption rather than damage to the annulus fibrosus.
The success of this procedure is based on decompression of the disc space by producing a hole in the annulus with the cutting probe and evacuating the nuclear material with the cutting and suction probe.
Medtronic introduced Profile 3D Annuloplasty Ring with a design based on the geometry of the saddle-shaped human mitral annulus to promote natural function with the aim of repairing rather than replacing a failing mitral valve.
Medtronic introduced Profile 3D Annuloplasty Ring with a design is based on the geometry of the saddle-shaped human mitral annulus to promote natural function with the aim of repairing rather than replacing a failing mitral valve.
On the other hand, the annulus fibrosus occupies 40-60% of the disc volume.
This works for wells without packers where the annulus can be used as a pressure charge chamber.
A downhole piece of equipment in a tubing string that allows flow from annulus to tubing.
Sequenced cement jobs that are placed through different entry points into the annulus.
Undertaken to place a higher cement column in the annulus when the fracturing gradient of the exposed formations will not tolerate a full column of cement.
Short screens used at the top and bottom of older gravel packing assemblies to help determine where the gravel is within the screen by casing annulus during packing.
In a well, the U- tube is represented by the tubing and the annulus with the bottom of tubing as the low spot.

In science:

Figure 2: Identification of annuli We identify each annulus Ans and the point Ps with their images in F (Γ) respectively.
The solution to a conjecture of Tits on the subgroup generated by the squares of the generators of an Artin group
The spectrum of a circular free Poission element of parameter c has been found by Haagerup and Larsen to be the annulus centered at zero with radii √c − 1 and √c, if c > 1, whereas the spectrum of the circular operator is the disk of radius 1.
Invariant subspaces of Voiculescu's circular operator
Let e be an integer, and C = Sp(K hz , ti/z t − πe ) be the annulus {z ∈ Ω; 0 ≤ v(z ) ≤ e}.
Ramification of local fields with imperfect residue fields
In the Cardy case, this leads to the result Aab (t) = Xν∈I which tells us that the so-called annulus multiplicities are equal to the fusion rules.
Conformal field theory, boundary conditions and applications to string theory
The annulus is a one-loop diagram, too, and we will interpret it as the partition function for open string states.
Conformal field theory, boundary conditions and applications to string theory