Question

alternate
al·ter·nate
I
 /ˈɑːltɚˌneıt/  verb  , -nates, -nat·ed, -nat·ing
  : to place or do (different things) so that one follows the other in a repeated series
   [  + obj  ] To make the appetizer, you should alternate layers of tomatoes and cheese. [=you should place a layer of tomatoes, then a layer of cheese, then a layer of tomatoes, etc.]
    The poem/poet alternates fear and hope.
    — often + with
    The necklace is made by alternating glass beads with shells.
    The poem/poet alternates fear and hope with each other. = The poem/poet alternates fear with hope.
   
   [  no obj  ] The light and dark woods alternate to form an elegant pattern around the window.
    — often + with
    Light woods alternate with dark woods.
   
    — often + between
    The poem alternates between fear and hope.
    He alternates between riding his bike and taking the bus to work.
   
  alternating  adj  
   To make the appetizer, you should use alternating layers of tomatoes and cheese.
   The shirt has alternating red and yellow stripes.
  al·ter·na·tion /ˌɑːltɚˈneıʃən/  noun  ,  pl   -tions [  count  ,  noncount  ]
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al·ter·nate
II
 /ˈɑːltɚnət, Brit ˌɔːlˈtəːnət/  adj  
  1 : occurring in or forming a repeated series
   alternate sunshine and rain
   Alternate shades of wood formed a pattern around the window.
  2
  — used to describe something that happens one time, does not happen the next time, happens again, etc.
   The fair is held on alternate years. [=the fair is held every other/second year; the fair is held one year, not held the next year, held the following year, and so on]
   She picks the children up from school on alternate days. [=(for example) she picks up the children on Monday, Wednesday, and Friday]
  3 chiefly US : other than the usual : alternative
   We took an alternate route because of the traffic.
   Due to an emergency, the plane landed at an alternate airport.
  al·ter·nate·ly  adv  
   The poem is alternately fearful and hopeful.
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al·ter·nate
III
 /ˈɑːltɚnət, Brit ˌɔːlˈtəːnət/  noun  ,  pl   -nates [  count  ]
   US   : someone who is chosen to take another person's place if that person is not able to be present or to do a required job
   The town has elected five councilors and two alternates.
   an alternate juror