ortho

[ awr-thoh ]
/ ˈɔr θoʊ /

adjective Chemistry.

pertaining to or occupying two adjacent positions in the benzene ring. Compare meta2, para3.

Origin of ortho

First recorded in 1875–80; independent use of ortho-

Words nearby ortho

orth., orthergasia, orthesis, orthetics, orthicon, ortho, ortho-, ortho-cousin, ortho-dichlorobenzene, ortho-kung t cell, ortho-nitrophenol

Definition for ortho (2 of 2)

ortho-

a combining form occurring in loanwords from Greek, where it meant “straight,” “upright,” “right,” “correct” (orthodox) and on this model used in the formation of compound words (orthopedic).
Chemistry.
  1. a combining form used in the name of that acid in a given series of acids that contains the most water (orthoboric acid).Compare meta-, pyro-.
  2. a combining form used in the names of the salts of these acids: if the acid ends in -ic, the corresponding salt ends in -ate (orthoboric acid (H3BO3) and potassium orthoborate (K3BO3)); if the acid ends in -ous, the corresponding salt ends in -ite (orthoantimonous acid (H3SbO3) and potassium orthoantimonite (K3SbO3)).
Also especially before a vowel, orth-.

Origin of ortho-

< Greek, combining form of orthós straight, upright, correct

Example sentences from the Web for ortho

British Dictionary definitions for ortho

ortho-

before a vowel orth-

combining form

straight or upright orthotropous
perpendicular or at right angles orthoclastic
correct or right orthodontics; orthodox; orthography; orthoptics
(often in italics) denoting an organic compound containing a benzene ring with substituents attached to adjacent carbon atoms (the 1,2- positions) orthodinitrobenzene Abbreviation: o- Compare oarsman Compare oarsman
denoting an oxyacid regarded as the highest hydrated form of the anhydride or a salt of such an acid orthophosphoric acid See meta- (def. 6)
denoting a diatomic substance in which the spins of the two atoms are parallel orthohydrogen See para- 1 (def. 8)

Word Origin for ortho-

from Greek orthos straight, right, upright

Medical definitions for ortho

ortho-

pref.

Straight; upright; vertical:orthotropic.
Correct; correction:orthopsychiatry.
Hydrated form of an acid or of its salts:orthoboric acid.
Diatomic molecules in which the nuclei have the same direction of spin:orthohydrogen.
Of or relating to one of three possible isomers of a benzene ring with adjacent carbon atoms having attached chemical groups:ortho-dibromobenzene.