Versus is defined as in contrast to or opposing.(preposition)
An example of versus used as a preposition is in the phrase "the red team versus the blue team."
See versus in Webster's New World College Dictionary
Origin: ML < L, toward, turned in the direction of < vertere, to turn: see verse
See versus in American Heritage Dictionary 4
Origin: Middle English
Origin: , from Medieval Latin
Origin: , from Latin, turned, toward
Origin: , from past participle of vertere, to turn; see wer-2 in Indo-European roots.