† rotumben.

Etymology: < post-classical Latin rotumba (13th cent. in a British source) < Spanish redoma , †rotoma (10th cent. as aredoma , arrotoma ) and its cognate Portuguese redoma , †rodoma (10th cent as arrodoma ), of uncertain origin (see below). The Latin and Romance forms in ro- perhaps show influence from classical Latin rotundus rotund adj. Compare Middle French retombe, redombe, retumbe (late 12th cent. in Old French as retonbe), Old Occitan retomba (late 12th cent.), Catalan †retoma (13th cent.). J. Corominas Diccionario crítico etimológico castellano e hispánico (1981) at redoma suggests that Spanish redoma may be < Maghribi Arabic rḍuma ‘bottle’, but this is not attested until much later and, given its geographical distribution, may well show a borrowing < Spanish (in which case the Spanish noun is itself of unknown origin). Alternatively, a derivation < an unattested Spanish Arabic form *raṭūma or *ruṭūma, use as noun of the feminine of Arabic raṭūm narrow (used especially of the vagina), has been suggested, but presents semantic problems.