What does adrenaline mean?
Adrenaline is a hormone produced by the adrenal glands, small organs sitting atop the kidneys. When the brain perceives danger, excitement, or intense stress, it triggers a rapid release of adrenaline into the bloodstream, causing the heart to beat faster, breathing to quicken, and blood sugar to rise — the classic 'fight or flight' response that prepares the body for sudden action. In medicine, the same substance is known as epinephrine, particularly in the United States, where that name is standard in clinical settings; British usage favours 'adrenaline'. Beyond physiology, the word has taken on a vivid figurative life: people speak of an 'adrenaline rush' or call thrill-seekers 'adrenaline junkies', using the hormone's name to capture any surge of exhilaration or heightened alertness. This blend of precise scientific meaning and energetic everyday metaphor makes 'adrenaline' one of the most recognisable words associated with excitement, courage, and the body's remarkable capacity to respond under pressure.
A hormone secreted by the adrenal glands in response to stress, increasing heart rate, blood pressure, and energy availability; also called epinephrine.
"Adrenaline flooded his system the moment he heard the smoke alarm."
In medical contexts, especially in the United States, 'epinephrine' is the preferred term; 'adrenaline' dominates general and British usage.
A feeling of intense excitement, energy, or heightened alertness, likened to the physiological effect of the hormone.
"She lives for the adrenaline of performing live in front of thousands."
This figurative sense is informal but widely accepted, most often appearing in phrases like 'adrenaline rush'.
Rarely used in the plural; 'adrenaline' is almost always treated as an uncountable mass noun referring to the hormone or the feeling.
"Different situations trigger different kinds of adrenalines in athletes, from fear to pure elation."
The word 'adrenaline' literally means 'near the kidney' — because the glands that produce it sit right on top of them.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of adrenaline
The word 'adrenaline' derives from 'adrenal', which combines the Latin prefix 'ad-' ('toward' or 'at') with 'renes' ('kidneys'), referring to the glands located above them. The term was coined around the turn of the twentieth century, shortly after the hormone was isolated from adrenal gland extracts by Japanese chemist Jokichi Takamine, who patented the purified preparation under this name. Its American medical counterpart, 'epinephrine', comes from Greek roots meaning 'upon the kidney'. Both names thus encode the same anatomical observation in different classical languages.
Related word forms
How adrenaline is actually used
In British English 'adrenaline' is the standard term; American medical writing prefers 'epinephrine', though 'adrenaline' remains common in everyday US speech. The figurative sense ('an adrenaline rush') is informal but fully accepted.
Easily confused with adrenaline
Epinephrine is simply the preferred medical name in the United States for the same substance called adrenaline elsewhere; neither is a different compound.