'chubby' originates from the English dialect word 'chub', which referred to a type of fish known for its plumpness.

'chub' was used in Middle English to describe a plump fish, and eventually evolved into the adjective 'chubby' to describe a plump or rounded appearance.

Initially, it referred to the plumpness of a fish, but over time it evolved to describe a rounded or plump appearance in general.