fridge n.

shortened and altered form of refrigerator, 1926, an unusual way of word-formation in English; perhaps influenced by Frigidaire (1919), name of a popular early brand of self-contained automatically operated iceless refrigerator (Frigidaire Corporation, Detroit, Michigan, U.S.), a name suggesting Latin frigidarium "a cooling room in a bath." Frigerator as a colloquial shortening is attested by 1886.