merinoPronunciation: /məˈriːnəʊ/Definition of merino noun (plural merinos) (also merino sheep) a sheep of a breed with long, fine wool. [mass noun] a soft woollen or wool-and-cotton material resembling cashmere, originally of merino wool. [mass noun] a fine woollen yarn. West Indian an undershirt, originally one made of merino wool. Origin: late 18th century: from Spanish, of unknown originmerino in other Oxford dictionaries Definition of merino in the US English dictionary