A quantity of food sufficient to fill one's stomach; as much as the belly can comfortably hold.
From 'belly' and 'full,' meaning completely filled. This forms a direct compound describing the maximum capacity of one's stomach, used since Middle English.
Bellyfull appears in medieval literature to mean 'enough' in the sense of 'I've had a bellyfull of this nonsense'—making your stomach the metaphor for tolerance itself!
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