‘汗衫’ (hàn shān) literally means ‘sweat shirt’ — combining 汗 (hàn), meaning ‘sweat’, and 衫 (shān), a classical term for a loose-fitting upper-body garment, often used in compound words for shirts or tops. Historically, it referred to a simple, sleeveless or short-sleeved cotton undershirt worn next to the skin to absorb sweat, especially in hot weather or during physical labor. Today, it remains widely used across China and other Chinese-speaking regions to refer to a basic, lightweight undershirt — similar to what English speakers call a ‘vest’ (UK) or ‘tank top’ (US), though typically more utilitarian and less fashion-oriented.

The word carries a neutral, slightly traditional or colloquial tone — common in everyday speech, clothing labels, and informal descriptions. It’s distinct from formal dress shirts (衬衫, chènshān) and modern athletic base layers; 汗衫 emphasizes simplicity, breathability, and function over style. While still widely understood, younger urban speakers may occasionally use loanwords like 背心 (bèixīn) interchangeably, though 背心 can also mean ‘sleeveless sweater’ depending on context.