容器 (róng qì) literally combines 容 (róng), meaning 'to hold' or 'to contain', and 器 (qì), meaning 'utensil' or 'implement'. Together, they form a general term for any object designed to hold, store, or transport something—such as bottles, boxes, tanks, or bowls. It’s a neutral, formal noun commonly used in daily life, science, logistics, and manufacturing contexts.

Unlike more specific words like 瓶子 (bottle) or 盒子 (box), 容器 emphasizes function over form: the key idea is capacity and containment, not shape or material. It appears frequently in instructions ('Please use a clean container'), safety guidelines ('Store chemicals in a sealed container'), and technical descriptions ('The reactor contains a stainless-steel container'). It can refer to physical objects or, abstractly, to data structures in computing (e.g., 'container format').