'athodyd' originates from Welsh, specifically the Welsh word 'athodyd' (used in Welsh to mean a preface or introductory piece).

'athodyd' was borrowed into English from Welsh in the 19th century, entering English usage as a rare literary term meaning a prefatory or introductory composition.

Initially and historically it has referred to an introductory or prefatory piece; its meaning in English has remained close to that original sense, though its use in English has been rare and chiefly literary.