ortho

[ awr-thoh ]

adjectiveChemistry.
  1. pertaining to or occupying two adjacent positions in the benzene ring.: Compare meta3, para3.

Origin of ortho

1
First recorded in 1875–80; independent use of ortho-

Words Nearby ortho

Other definitions for ortho- (2 of 2)

ortho-

  1. 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).

  2. Chemistry.

    • 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-.

    • 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)).

Origin of ortho-

2
<Greek, combining form of orthós straight, upright, correct
  • Also especially before a vowel, orth-.

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How to use ortho in a sentence

British Dictionary definitions for ortho-

ortho-

combining form
  1. straight or upright: orthotropous

  2. perpendicular or at right angles: orthoclastic

  1. correct or right: orthodontics; orthodox; orthography; orthoptics

  2. (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

  3. 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)

  4. denoting a diatomic substance in which the spins of the two atoms are parallel: orthohydrogen See para- 1 (def. 8)

Origin of ortho-

1
from Greek orthos straight, right, upright

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012