step-down I. \ˈ ̷ ̷| ̷ ̷\adjective Etymology:step down : that decreases, reduces, or retards; specifically: that decreases voltage < step-down transformer > II. \ˈ ̷ ̷ˌ ̷ ̷\noun (-s) : a decrease or reduction in size or amount < a step-down in dosage >