[vi.tal] adj [ME, fr. MF, fr. L vitalis of life, fr. vita life; akin to L vivere to live--more at quick] (14c) 1 a: existing as a manifestation of life b: concerned with or necessary to the maintenance of life "~ organs" "blood and other ~ fluids"
2: full of life and vigor: animated
3: characteristic of life or living beings
4. a: fundamentally concerned with or affecting life or living beings: as (1): tending to renew or refresh the living: invigorating (2): destructive to life: mortal b: of the utmost importance
5: recording data relating to lives
6: of, relating to, or constituting the staining of living tissues syn see essential -- vi.tal.ly adv