vital (adj.) Look up vital at Dictionary.com
late 14c., "of or manifesting life," from Latin vitalis "of or belonging to life," from vita "life," related to vivere "to live," from PIE root *gwei- "to live." The sense of "necessary or important" is from 1610s, via the notion of "essential to life" (late 15c.). Vital capacity recorded from 1852. Related: Vitally.