versus (prep.) Look up versus at Dictionary.com
mid-15c., in legal case names, denoting action of one party against another, from Latin versus "turned toward or against," from past participle of vertere (frequentative versare) "to turn, turn back, be turned, convert, transform, translate, be changed," from PIE *wert- "to turn, wind," from root *wer- (3) "to turn, bend" (cognates: Old English -weard "toward," originally "turned toward," weorthan "to befall," wyrd "fate, destiny," literally "what befalls one;" Sanskrit vartate "turns round, rolls;" Avestan varet- "to turn;" Old Church Slavonic vrŭteti "to turn, roll," Russian vreteno "spindle, distaff;" Lithuanian ver čiu "to turn;" Greek rhatane "stirrer, ladle;" German werden, Old English weorðan "to become" (for sense, compare turn into); Welsh gwerthyd "spindle, distaff;" Old Irish frith "against").