annulus
Definition from Wiktionary, a free dictionary
Contents |
[edit] English
[edit] Noun
annulus (plural annuluses or annuli)
- A ring- or donut-shaped area or structure.
- (mathematics) The region between two concentric circles of different radius.
- (astronomy) The ring of the sun not covered by the moon in an annular solar eclipse.
- (botany) Structure in a fern that consists of differentially thick-walled cells on a sporangium that bend and distort as a result of drying.
- (mycology) The membranous remnants of a partial veil which leaves a ring on the stem of a mushroom.
- (oil and gas production) The space contained between the centre well bore and any external tubing. Sometimes used for separated gas flow.
