(sek′ən·der′ē) adjective
1. Of second rank, grade, or influence; subordinate; auxiliary; subsequent; resultant.
2. Depending on what is primary or original.
3. Ornithol. Of or pertaining to the secondaries of a bird's wings.
4. Electr. Of, pertaining to, or noting an induced current or its circuit, especially in an induction coil.
5. Chem. Formed by replacement of atoms or radicals in the molecules of certain organic compounds: a secondary alcohol.
6. Geol. Subsequent in origin; involving some chemical or physical change of the original mineral: contrasted with primary.
7. Pertaining to instruction in a secondary school.
—noun plural ·dar·ies
1. One who acts in a secondary or subordinate capacity; an assistant; a deputy or delegate.
2. Anything of secondary size, position, or importance.
3. A secondary planet; a satellite.
4. Ornithol. One of the feathers that grow on the second joint or forearm of a bird's wing. See illustrations under BIRD, FOWL.
5. One of the hind wings of an insect.
—sec′on·dar′·i·ly adverb

(sek′ən·der′ē) noun Geol.
1. The Mesozoic era.
2. The rocks formed in this era.
—adjective Belonging to or occurring in the Mesozoic era.