Lifeblood

Lifeblood has two related senses. In biology, lifeblood refers to blood—the circulating fluid in humans and other animals that sustains life. Blood carries oxygen and nutrients, removes waste, supports immune defenses, and contributes to clotting and temperature regulation.

In figurative use, lifeblood describes something vital to the health and functioning of a system, such as an economy, organization, or community. When the lifeblood of a sector is disrupted, growth slows, operations falter, or a community suffers; sustaining it is often a policy or management priority.

Etymology and usage: The term combines life and blood and has been used in English for centuries to convey essential vitality. In modern language, it appears across journalism, business, and literature to emphasize critical importance.

The concept reflects a dual idea: blood as a literal, life-sustaining fluid in biology, and lifeblood as a metaphor for anything deemed indispensable to the continued functioning and health of a system.