安眠 (ān mián) literally combines 安 (ān), meaning 'peaceful, safe, calm', and 眠 (mián), meaning 'to sleep'. Together, they form a noun meaning 'peaceful sleep' — sleep that is deep, undisturbed, and restorative. It emphasizes the quality of tranquility and mental ease during slumber, not just the physical act of sleeping.

This term is commonly used in health, medical, or wellness contexts — for example, when discussing sleep hygiene, insomnia treatments, or herbal remedies that promote rest. It appears in compound words like 安眠药 (ān mián yào, 'sleeping pill') and 安眠效果 (ān mián xiàoguǒ, 'sleep-inducing effect'). While it can appear in literary or poetic writing to evoke serenity, it is rarely used in casual daily speech to describe ordinary sleep — for that, people usually say 睡觉 (shuìjiào) or 睡眠 (shuìmián).