A century ago, the German botanist Hans Winkler (best known for coining the term ‘genome’) accomplished two novel transplantations. First, he produced a single plant that grafted together two completely disparate species: tomato and nightshade. Second, he chose the descriptive word ‘chimaera’ to name his innovation, transplanting the term from mythology to biology. This paper features Mrs McK, the first human chimera, and thus follows the term from botany to clinical medicine. Her remarkable story, pieced together from the notes, drafts and correspondence of Robert Race and his colleagues at the MRC Blood Group Unit, draws attention to the significance of names and naming.