"pertaining to spring," 1530s, from Late Latin vernalis "of the spring," from vernus "of spring," from Latin ver "the spring, spring-time," from PIE *wesr- "the spring" (source also of Old Norse var "spring," Greek ear, Armenian gar-un, Sanskrit vasantah, Persian bahar, Old Church Slavonic vesna "spring," Lithuanian vasara "summer").
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<a href="https://www.etymonline.com/word/ver">Etymology of ver by etymonline</a>
Harper, D. (n.d.). Etymology of ver. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/ver