Definition
A substance that increases the production of urine by the kidneys, causing the body to lose water and electrolytes faster than normal. Common diuretics include caffeine (coffee, tea, many soft drinks, energy drinks) and alcohol.
Plain English
Something you eat or drink that makes you urinate more often, causing your body to lose fluid faster than usual.
Context Anchor
Seen in aeromedical discussions about dehydration, heat, alcohol, caffeine, and medication use before or during flight.
Derivation
From Greek 'diouretikos', meaning 'promoting urine'. The root 'oûron' means urine. Knowing this helps because the word's whole purpose is to describe substances that pull water out of the body through urination.
Why Pilots Care
Diuretics speed up fluid loss and can quickly worsen dehydration, impairing judgment, reaction time, and heat tolerance during flight.
Intuition Check
Do not assume a liquid helps hydration just because you drink it. If it makes you urinate more and lose extra fluid, it can act as a diuretic.
Example Sentence 1
Knowing that coffee is a diuretic, the pilot switched to water during the long cross-country to stay properly hydrated.
Example Sentence 2
Certain prescription medications are diuretics and require extra attention to fluid intake on hot days.