Meaning of ALTERNATE in English
( a. )
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.
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012