stimulant
definition of stimulant
1. an agent that excites functional activity. A term often
loosely applied. Stimulants are diffusible when they excite the
circulation and general functions of the body; nervous, when they act
chiefly upon the nerve centers; hepatic, when they arouse the
functions of the liver; cardiac, when they increase the heart’s action;
gastric, when they quicken digestion; respiratory, when they increase
respiratory movements; etc. Also applied to medicines in which the
action of the contained ethyl alcohol is desired.1
2. a substance that increases brain activity, alertness, attention, blood pressure, heart rate, breathing, and energy.2