gʷeyh₃-tó-
“alive, living”Source of Latin vīvus, vīta, English vivid, vital, viable
Past participle of the live root, yielding Latin vīvus and English vivid, vital, viable, revive.
Discussion
The Proto-Indo-European form *gʷeyh₃-tó- is a past participle meaning "alive, living" and is built from the root *gʷeyh₃- "to live" with the participial suffix *-tó-. This formation was a standard Proto-Indo-European method of creating adjectives from verbal roots, and *gʷeyh₃-tó- meant literally "having been brought to life" or simply "alive". The form is the direct ancestor of an important branch of "life" vocabulary in the Italic languages.
In Latin, the form developed into vita "life" (via intermediate stages *gʷīwotā or similar), which became one of the most productive bases for English vocabulary: vital (essential to life), vitality, vitamin (a "life-amine", coined in 1912 by Casimir Funk, who believed these essential nutrients contained an amine group — the -e was later dropped when this proved not always true), revitalise, and devitalise. The Latin adjective vitalis "of or pertaining to life" produced English vital, which retains the original meaning with remarkable directness.
The word victual (food, provisions — literally "that which sustains life") is also derived from vita through Latin victualia, though the spelling has been re-Latinised. The curriculum vitae (literally "the course of life") preserves the genitive form vitae in everyday academic usage.
The relationship between *gʷeyh₃-tó- and its parent root *gʷeyh₃- illustrates the Proto-Indo-European system of derivational morphology. Where the root *gʷeyh₃- produced the verbal sense "to live" (seen in Latin vivere, English quick, Greek bios), the participial *gʷeyh₃-tó- produced the nominal-adjectival sphere — the state of being alive, life as a noun, and all that pertains to living. The two formations divided the semantic territory between them, with the participle specialising in the result state rather than the ongoing process.