alternate
Cross references: 1. intermittent 1. al.ter.nate \'o.l-t*r-n*t, 'al-\ aj [L alternatus, pp. of alternare, fr. alternus alternate, fr.]alter 1a: occurring or succeeding by turns 1b: RECIPROCATING 2a: arranged first on one side and then on the other at different levels o r points along an axial line 2b: arranged one above or alongside the other 3: every other : every second 4: ALTERNATIVE, SUBSTITUTE - al.ter.nate.ly av 2. al.ter.nate \-.na-t\ vt 1: to perform by turns or in succession 2: to cause to alternate : to happen, succeed, or act by turns 3. al.ter.nate \-n*t\ n 1: ALTERNATIVE 2: one that takes the place of or alternates with another
Webster's English Dictionary