al·ter·nate • v. / ˈôltərˌnāt/ [intr.] occur in turn repeatedly: the governorship alternated between the Republican and Democratic parties. ∎  [tr.] do or perform in turn repeatedly: some adults who wish to alternate work with education.• adj. / ˈôltərnit/ (abbr.: alt.) 1. every other; every second: she was asked to attend on alternate days. ∎  (of two things) each following and succeeded by the other in a regular pattern: alternate bouts of intense labor and of idleness. ∎  (of a sequence) consisting of alternate items. ∎  Bot. (of leaves or shoots) placed alternately on the two sides of the stem.2. taking the place of; alternative: alternate routes.• n. / -nit/ (abbr.: alt.) a person who acts as a deputy or substitute.DERIVATIVES: al·ter·nate·ly / -nitlē/ adv.al·ter·na·tion / ˌôltərˈnāshən/ n.

alternate adj. XVI. — L. alternātus, pp. of alternāre do things by turns, f. alternus, f. alter one or other of two, second.
So alternate vb. XVI; cf. F. alterner; see -ATE2, -ATE3. alternation XV. — F. or L. alternative adj. XVI, sb. XVII. — medL.; see -ATIVE.