Adrenalin is a hormone produced by the adrenal glands that is responsible for the body's "fight or flight" response in stressful situations. There are several synonyms for this word, including epinephrine, which is the medical term for adrenalin. Other synonyms include adrenaline, noradrenalin, and norepinephrine. These terms are often used interchangeably, although they refer to slightly different hormones with similar effects. No matter the word used, the feeling of adrenalin pumping through the body can be exhilarating and brings a sense of heightened alertness, readiness, and energy to deal with challenges and emergencies.