rondel vs sphere

rondel

noun
  • A rondelle, (small) circular object. 

  • A small round tower erected at the foot of a bastion. 

  • A long thin medieval dagger with a circular guard and a circular pommel (hence the name). 

  • A metric form of verse using two rhymes, usually fourteen 8- to 10-syllable lines in three stanzas, with the first lines of the first stanza returning as refrain of the next two. 

  • The verse form rondeau. 

sphere

noun
  • A spherical physical object; a globe or ball. 

  • The region in which something or someone is active; one's province, domain. 

  • A regular three-dimensional object in which every cross-section is a circle; the figure described by the revolution of a circle about its diameter . 

  • The set of all points in three-dimensional Euclidean space (or n-dimensional space, in topology) that are a fixed distance from a fixed point . 

  • Any of the concentric hollow transparent globes formerly believed to rotate around the Earth, and which carried the heavenly bodies; there were originally believed to be eight, and later nine and ten; friction between them was thought to cause a harmonious sound (the music of the spheres). 

  • The extension of a general conception, or the totality of the individuals or species to which it may be applied. 

  • An area of activity for a planet; or by extension, an area of influence for a god, hero etc. 

verb
  • To place in a sphere, or among the spheres; to ensphere. 

  • To make round or spherical; to perfect. 

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