‘睡裤’ (shuì kù) literally combines 睡 (shuì, 'to sleep') and 裤 (kù, 'pants' or 'trousers'), meaning 'sleep pants' — loose, comfortable trousers worn specifically for sleeping or relaxing at home. Unlike regular trousers, 睡裤 are typically made of soft, breathable fabrics like cotton or fleece and often feature elastic waists and relaxed fits. They’re part of a broader category of sleepwear in Chinese, which includes 睡衣 (shuìyī, 'pajamas') and 睡裙 (shuìqún, 'nightgown').

This term is neutral and widely used in everyday speech and retail contexts. While not formal, it’s common in conversations about bedtime routines, laundry, shopping, or packing for travel. It’s distinct from workout pants or loungewear — its primary function is rest, not activity. Parents may use it when dressing young children for bed, and adults often refer to it when choosing cozy attire for evenings at home.