'Lifeblood' definitions:

Definition of 'lifeblood'

(from WordNet)
noun
The blood considered as the seat of vitality
noun
An essential or life-giving force; "water is the lifeblood of India"

Definition of 'Lifeblood'

From: GCIDE
  • Lifeblood \Life"blood`\ (l[imac]f"bl[u^]d`), n.
  • 1. The blood necessary to life; vital blood. --Dryden. [1913 Webster]
  • 2. Fig.: That which gives strength and energy. [1913 Webster]
  • Money [is] the lifeblood of the nation. --Swift. [1913 Webster]

Synonyms of 'lifeblood'

From: Moby Thesaurus