TERMIUM Plus®

The Government of Canada’s terminology and linguistic data bank.

1 3 [2 records]

Record 1 2004-04-30

English

Subject field(s)
  • Chemistry
CONT

ortho: A prefix meaning "straight ahead"; "meta" means "beyond"; "para" means "opposite". These prefixes are used in organic chemistry in naming disubstitution products derived from benzene in which the substituent atoms or radicals are located in certain definite positions on the benzene ring. This is illustrated in the diagram [not reproduced on this record], where A and B represent the substituent atoms or groups. When attached to adjoining carbon atoms, B is in the ortho position in respect to A (also called the 1,2-position). If B is located on the third carbon atom in respect to A, it is in the meta position (also called 1,3-); when B is attached to the opposite carbon atom, it is the para position (1,4).

OBS

The prefixes "ortho-", "meta-" and "para-", along with their corresponding abbreviations ("o-", "m-" and "p-"), appear in italics and are ignored in alphabetizing. According to the actual chemical nomenclature rules in organic chemistry (in 2003), the numbers designating the positions of the disubstitution groups (1,2- for "ortho-", 1,3- for "meta-" and 1,4- for "para-") are to be preferred to the symbols "o-", "m-" and "p-". Furthermore, the prefixes "ortho-", "meta-" and "para-" should not be used anymore, and their corresponding abbreviations ("o-", "m-", and "p-") will soon be judged to be avoided, if not totally condemned.

OBS

In inorganic chemistry the prefix ortho- designates the most highly hydrated acid, or its salt, to contrast with the meta- or less hydrated acid or salt.

Key term(s)
  • meta
  • m
  • 1,3

French

Domaine(s)
  • Chimie
DEF

Préfixe employé en chimie organique pour désigner les dérivés du benzène disubstitués aux positions 1 et 3.

OBS

[Aussi employé] en chimie minérale pour former le nom de certains acides et de leurs dérivés.

OBS

Les préfixes de position «ortho-», «méta-» et «para-», tout comme les abréviations correspondantes «o-», «m-» et «p-», s'écrivent en italique et n'interviennent pas dans une classification par ordre alphabétique. Selon les règles de nomenclature de chimie organique en vigueur aujourd'hui (en 2003), il est recommandé d'utiliser les chiffres 1,2-, 1,3- et 1,4-, respectivement. Les préfixes «ortho-», «méta-» et «para-» ne doivent plus être utilisés. L'usage des symboles correspondants («o-», «m-» et «p-») sera bientôt fortement déconseillé, sans être exclu.

Key term(s)
  • méta
  • m
  • 1,3

Spanish

Save record 1

Record 2 2004-04-30

English

Subject field(s)
  • Chemistry
CONT

ortho: A prefix meaning "straight ahead"; "meta" means "beyond"; "para" means "opposite". These prefixes are used in organic chemistry in naming disubstitution products derived from benzene in which the substituent atoms or radicals are located in certain definite positions on the benzene ring. This is illustrated in the diagram [not reproduced on this record], where A and B represent the substituent atoms or groups. When attached to adjoining carbon atoms, B is in the ortho position in respect to A (also called the 1,2-position). If B is located on the third carbon atom in respect to A, it is in the meta position (also called 1,3-); when B is attached to the opposite carbon atom, it is the para position (1,4).

OBS

The prefixes "ortho-", "meta-" and "para-", along with their corresponding abbreviations ("o-", "m-" and "p-"), appear in italics and are ignored in alphabetizing. According to the actual chemical nomenclature rules in organic chemistry (in 2003), the numbers designating the positions of the disubstitution groups (1,2- for "ortho-", 1,3- for "meta-" and 1,4- for "para-") are to be preferred to the symbols "o-", "m-" and "p-". Furthermore, the prefixes "ortho-", "meta-" and "para-" should not be used anymore, and their corresponding abbreviations ("o-", "m-", and "p-") will soon be judged to be avoided, if not totally condemned.

OBS

In inorganic chemistry the prefix ortho- designates the most highly hydrated acid, or its salt, to contrast with the meta- or less hydrated acid or salt.

Key term(s)
  • para
  • p
  • 1,3

French

Domaine(s)
  • Chimie
DEF

Préfixe qui s'applique aux dérivés du benzène disubstitués aux positions 1 et 4 et qui est employé également pour désigner des oligomères.

OBS

Les préfixes de position «ortho-», «méta-» et «para-», tout comme les abréviations correspondantes «o-», «m-» et «p-», s'écrivent en italique et n'interviennent pas dans une classification par ordre alphabétique. Selon les règles de nomenclature de chimie organique en vigueur aujourd'hui (en 2003), il est recommandé d'utiliser les chiffres 1,2-, 1,3- et 1,4-, respectivement. Les préfixes «ortho-», «méta-» et «para-» ne doivent plus être utilisés. L'usage des symboles correspondants («o-», «m-» et «p-») sera bientôt fortement déconseillé, sans être exclu.

Key term(s)
  • para
  • p
  • 1,4

Spanish

Save record 2

Copyright notice for the TERMIUM Plus® data bank

© Public Services and Procurement Canada, 2024
TERMIUM Plus®, the Government of Canada's terminology and linguistic data bank
A product of the Translation Bureau

Features

Language Portal of Canada

Access a collection of Canadian resources on all aspects of English and French, including quizzes.

Writing tools

The Language Portal’s writing tools have a new look! Easy to consult, they give you access to a wealth of information that will help you write better in English and French.

Glossaries and vocabularies

Access Translation Bureau glossaries and vocabularies.

Date Modified: