octavo vs recto

octavo

noun
  • A book of octavo pages. 

  • A sheet of paper 7 to 10 inches (= 17.78 to 25.4 cm) high and 4.5 to 6 inches (= 11.43 to 15.24 cm) wide, the size varying with the large original sheet used to create it. It is made by folding the original sheet three times to produce eight leaves. 

recto

noun
  • The right-hand page of a book of a script which reads from left to right, usually having an odd page number. 

  • A writ of right. 

  • The front side of a flat object which is to be examined visually, as for reading, such as a sheet, leaf, coin or medal. 

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