annulus vs hula hoop

annulus

noun
  • A ring- or donut-shaped area or structure. 

  • The ring of the sun not covered by the moon in an annular solar eclipse. 

  • Structure in a fern that consists of differentially thick-walled cells on a sporangium that bend and distort as a result of drying. 

  • The region in a plane between two concentric circles of different radii. 

  • The membranous remnants of a partial veil which leaves a ring on the stem of a mushroom. 

  • The space contained between the centre well bore and any external tubing. Sometimes used for separated gas flow. 

  • Any topological space homeomorphic to the region in a plane between two concentric circles of different radius. 

hula hoop

noun
  • A toy in the form of a large hoop which is twirled around various parts of the body, especially the waist. 

verb
  • To use a hula hoop. 

How often have the words annulus and hula hoop occurred in a corpus of books? (source: Google Ngram Viewer )