annular vs encircling

annular

adj
  • Banded or marked with circles. 

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

encircling

adj
  • enclosing, skirting 

noun
  • encirclement 

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