That which alternates with something else; vicissitude.

A substitute; an alternative; one designated to take the place of another, if necessary, in performing some duty.

A proportion derived from another proportion by interchanging the means.

To perform by turns, or in succession; to cause to succeed by turns; to interchange regularly.

To happen, succeed, or act by turns; to follow reciprocally in place or time; followed by with.

“The flood and ebb tides alternate with each other.”

To vary by turns.

“The land alternates between rocky hills and sandy plains.”

Happening by turns; one following the other in succession of time or place; first one and then the other (repeatedly)

“alternate picking is a guitar playing technique”

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.

“the alternate members 1, 3, 5, 7, etc.”

Other; alternative.

“He lives in an alternate universe and an alternate reality.”