snowball

the word 'snowball' is a transparent compound formed from two old english (germanic) elements. the first element, 'snow', descends from proto-germanic snaiwaz and ultimately from the proto-indo-european root sniegʷh-, meaning 'to snow'. the second element, 'ball', originates from a germanic root meaning 'round object'. the literal combination, meaning a ball made of snow, dates to the late middle english period. its figurative verbal sense, 'to increase rapidly like a rolling snowball gathering more snow', emerged in the 19th century, perfectly capturing the concept of exponential growth through a vivid, concrete metaphor.

Structure: snow + ball snow (from old english snāw, meaning frozen precipitation; the substance itself) + ball (from old english beall or old norse bǫllr, meaning a rounded mass or sphere; the shape/form).