noun
sleeping pill; sleep medication
General term for medication used to induce or maintain sleep, including both prescription and over-the-counter products.
昨夜はどうしても眠れなくて、睡眠薬を飲んだ。
Last night I couldn't sleep no matter what, so I took a sleeping pill.
Compound of 睡眠 (suimin, 'sleep') + 薬 (yaku, 'medicine, drug').