Scholars working in the field of oral epic all have a particular form of words committed to memory—Milman Parry's celebrated definition of the formula. The definition in fact appears in two slightly differing forms in Parry's writing. In 1928 he wrote, ‘In the diction of bardic poetry, the formula can be defined as an expression regularly used, under the same metrical conditions, to express an essential idea’ (Parry, 1971: 13). Two years later came the more familiar version: ‘The formula in the Homeric poems may be defined as a group of words which is regularly employed under the same metrical conditions to express a given essential idea’ (Parry, 1971: 272). The differences between the two forms of the definition are negligible, and Parry made no further attempt to refine or modify it during the five years of life that remained to him. For Albert Lord, too, the definition was clearly adequate as it stood: in ch. iii of The singer of tales he simply quotes it verbatim (Lord, 1960: 30), and proceeds directly to a consideration of the function of formulaic diction.