noun 1.Chemistry. an atom or atomic group that takes the place of another atom or group present in the molecule of the original compound.
adjective 2.having been or capable of being substituted.
Origin: 1890–95; <
Latin substituent- (stem of
substituēns), present participle of
substituere to
substitute, equivalent to
sub- sub- +
-stitu-, combining form of
statuere to set up, erect (see
statue) +
-ent- -ent