Definition: Decaffeinated means reduced caffeine content, typically below 5mg/100ml for regular coffee. Definition: - Reduced in caffeine content to avoid excessive alertness (deca) or restlessness when drinking, a popular term indicating it's low on caffeine compared to black or green tea. - Common among non-caffeine beverages like milk and water. Decaf coffee is often lower than the standard 37-40mg/100ml for regular coffee.