‘暖瓶’ (nuǎn píng) literally means ‘warm bottle’ — combining 暖 (nuǎn), meaning ‘warm’ or ‘heat-retaining’, and 瓶 (píng), meaning ‘bottle’ or ‘vessel’. It refers specifically to a vacuum-insulated thermos flask, commonly used in Chinese households and workplaces to keep hot water, tea, or soup hot for many hours. Unlike Western-style travel mugs, traditional Chinese 暖瓶 often features a metal or plastic outer shell with a glass liner and a stopper, and is frequently seen on desks, kitchen counters, or beside beds.

This word is neutral in register and widely understood across all age groups and regions of China. While modern usage sometimes includes stainless-steel vacuum flasks, the term 暖瓶 still evokes a classic, functional household item associated with daily warmth and practical care — especially in colder seasons or in homes without instant hot-water access. It’s rarely used metaphorically and almost always denotes a physical container designed for heat retention.