ortho- vs syn-

ortho-

prefix
  • Straight, right, proper. 

  • in isomeric benzene derivatives, having the two substituents in adjacent (2,6) positions (compare meta- and para-). 

  • Having an extra proportion of water. 

  • of any molecule of the form X₂ in which the two nuclei have parallel spin. 

syn-

prefix
  • concomitant 

  • with, together 

  • identical 

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