- In medicine and biology, a prefix denoting the concept of after, subsequent to, behind, or hindmost. Cf.:post-. [G. after, between, over]1. In chemistry, an italicized prefix denoting joint, action sharing. 2. (m-) In chemistry, an italicized prefix denoting a compound formed by two substitutions in the benzene ring separated by one carbon atom, i.e., linked to the first and third, second and fourth, etc., carbon atoms of the ring. For terms beginning with m., or m-, see the specific name. [G. after, between, over]
* * *meta- or met- prefix1) isomeric with or otherwise closely related to <metaldehyde>2) involving substitution at or characterized by two positions in the benzene ring that are separated by one carbon atom abbr. m- <meta-xylene or m-xylene> compare ORTH- (2), PARA- (2)
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* * *1. symbol m-; in organic chemistry, a prefix indicating a 1,3-substituted benzene ring, e.g., m-xylene (1,3-dimethylbenzene) or m-nitrophenol (3-nitrophenol). 2. in inorganic chemistry, a prefix indicating a polymeric acid anhydride, e.g., metaphosphoric acid.
Two examples of disubstituted benzene derivatives with substituents in the meta-position. (A), 1,3-dibromobenzene; (B), meta-xylene (1,3-dimethylbenzene).
Medical dictionary. 2011.