annular vs rotund

annular

adj
  • Pertaining to, or having the form of, a ring; ring-shaped; in the shape of an annulus. 

  • Banded or marked with circles. 

rotund

adj
  • Having a round, spherical or curved shape; circular; orbicular. 

  • Having a round body shape; portly or plump; podgy. 

  • Full and rich; orotund; sonorous; full-toned. 

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