a Succeeding next in order to the first; of second place, origin, rank, rank, etc.; not primary; subordinate; not of the first order or rate.
a Acting by deputation or delegated authority; as, the work of secondary hands.
a Possessing some quality, or having been subject to some operation (as substitution), in the second degree; as, a secondary salt, a secondary amine, etc. Compare primary.
a (geology) Subsequent in origin; -- said of minerals produced by alteration or deposition subsequent to the formation of the original rocks mass; also of characters of minerals (as secondary cleavage, etc.) developed by pressure or other causes.
a (zootomy) Pertaining to the second joint of the wing of a bird.
a (medicine) Dependent or consequent upon another disease; as, Bright's disease is often secondary to scarlet fever; or occurring in the second stage of a disease; as, the secondary symptoms of syphilis.