Al·ter·nate a.
 1. Being or succeeding by turns; one following the other in succession of time or place; by turns first one and then the other; hence, reciprocal.
    And bid alternate passions fall and rise.   --Pope.
 2. Designating the members in a series, which regularly intervene between the members of another series, as the odd or even numbers of the numerals; every other; every second; as, the alternate members 1, 3, 5, 7, etc. ; read every alternate line.
 3. Bot. Distributed, as leaves, singly at different heights of the stem, and at equal intervals as respects angular divergence.
 Alternate alligation. See Alligation.
 Alternate angles Geom., the internal and angles made by two lines with a third, on opposite sides of it. It the parallels AB, CD, are cut by the line EF, the angles AGH, GHD, as also the angles BGH and GHC, are called alternate angles.
 Alternate generation. Biol. See under Generation.