'jug-shaped' originates from English, formed from the noun 'jug' (from Middle English 'jugge') combined with the adjective-forming element '-shaped' (from 'shape', Old English 'gesceap'/'sceap'), where 'jugge' meant 'a pitcher or earthenware vessel' and 'shape' meant 'form'.

'jug' changed from Middle English 'jugge' to the modern English 'jug', and the compound pattern 'X-shaped' developed in Modern English by attaching '-shaped' to nouns (e.g. 'leaf-shaped'), producing 'jug-shaped' to describe items resembling a jug.

Initially it literally described objects having the form of a jug; over time the usage has remained essentially the same and continues to describe any object resembling a jug in outline.