ortho-phenylene From ortho- + phenylene. <span class="searchmatch">orthophenylene</span> (uncountable) (organic chemistry, in combination) The ortho- form of the phenylene radical....
substituents in adjacent (1,2) positions (compare meta- and para-). E.g. <span class="searchmatch">orthophenylene</span>, orthosubstitution, orthocleavage. (chemistry) Having an extra proportion...