(adj) performing an essential function in the living body, Syn. life-sustaining, Example:vital organs; blood and other vital fluids; the loss of vital heat in shock; a vital spot; life-giving love and praise
The Collaborative International Dictionary of English (GCIDE) v.0.53 Collaborative International Dictionary (GCIDE)
adj. being the seat or source of life; performing a necessary function in the living body; as, the need for life-sustaining air and water. Syn. -- vital. [ WordNet 1.5 +PJC ]