2. (Chem.) A prefix denoting:
(a) Other; duplicate, corresponding to; resembling; hence,
metameric; as, meta-arabinic, metaldehyde.
(b) (Organic Chem.) That two replacing radicals, in the
benzene nucleus, occupy the relative positions of 1
and 3, 2 and 4, 3 and 5, 4 and 6, 5 and 1, or 6 and 2;
as, metacresol, etc. See {Ortho-}, and {Para-}.
(c) (Inorganic Chem.) Having less than the highest number
of hydroxyl groups; -- said of acids; as,
metaphosphoric acid. Also used adjectively.