ortho-

 
Pronunciation: /ˈɔːθəʊ/

combiningForm

  • 1straight; rectangular; upright: orthodontics
  • right; correct: orthoepy
  • 2 Chemistry denoting substitution at two adjacent carbon atoms in a benzene ring, e.g. in 1,2 positions: orthodichlorobenzeneCompare with meta- and para-1.
  • 3 Chemistry denoting a compound from which a meta-compound is formed by dehydration: orthophosphoric acid

Origin:

from Greek orthos 'straight, right'