A small container or case, often a tiny shell filled with medicine, or a sealed unit like a space capsule.
It comes from Latin 'capsula', a small box, which is a diminutive of 'capsa', meaning 'box' or 'case'. The idea moved from simple little boxes to modern medical and space-technology containers.
A medicine capsule is literally a 'little box' you swallow. The same word is used for space capsules, which are like high-tech boxes carrying humans and experiments instead of powder and pills.
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