What does adrenalin mean?
Adrenalin is a hormone produced by the adrenal glands, small organs sitting atop the kidneys. When the brain perceives threat, stress, or intense excitement, adrenalin floods the bloodstream, quickening the heartbeat, raising blood pressure, and releasing glucose to fuel the muscles — the classic 'fight-or-flight' response. In medicine, the same substance is known as epinephrine and is used to treat severe allergic reactions and cardiac emergencies. Beyond biology, the word has taken on a vivid figurative life: people speak of an 'adrenalin rush' when describing the thrill of skydiving, competitive sport, public performance, or any high-stakes moment. Used this way, it connotes excitement, alertness, and raw energy rather than simple fear. The spelling 'adrenalin' (without a final 'e') is especially common in British English, while 'adrenaline' predominates elsewhere; both refer to exactly the same substance. It is an uncountable noun, so it takes no plural form.
A hormone secreted by the adrenal glands that increases heart rate, blood pressure, and energy availability as part of the body's stress response; chemically known as epinephrine.
"An injection of adrenalin can reverse the effects of a severe allergic reaction."
Uncountable; no plural form.
A feeling of intense excitement or heightened physiological arousal experienced during thrilling or dangerous situations.
"The crowd's roar sent a wave of adrenalin through the young athlete."
Adrenalin is a mass noun referring to a substance or a feeling, and is not used in the plural in standard English.
"Adrenalin was pumping through his veins as the race began."
Adrenalin was originally a brand name — registered by a pharmaceutical company in 1901 — before it became the everyday word for our fight-or-flight fuel.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of adrenalin
The word 'adrenalin' derives from 'adrenal', which combines the Latin prefix 'ad-' (toward) with 'renes' (kidneys), describing the glands located above the kidneys. The term originated as a proprietary name registered around 1901 by Parke, Davis & Company for the purified hormone they had isolated. Over time the trademark became genericized into ordinary English vocabulary. Its sibling form 'adrenaline' shares the identical root, and related medical terms such as 'adrenal' and 'adrenalectomy' trace back to the same Latin source.
Related word forms
How adrenalin is actually used
'Adrenalin' is uncountable in standard usage. The spelling without the final 'e' is common in British English and is the original commercial name; American English more often uses 'adrenaline'. In figurative use it carries connotations of excitement and vitality rather than fear alone.
Easily confused with adrenalin
Adrenaline is simply the longer spelling of the same hormone; 'adrenalin' is the original trademarked name and remains common in British English, while 'adrenaline' is more frequent overall.