n. (also grannie) (pl. -ies) colloq. grandmother. granny bond Brit. colloq. a form of National Savings certificate orig. available only to pensioners. granny flat (or annexe) Brit. part of a house made into self-contained accommodation for an elderly relative. granny knot a reef-knot crossed the wrong way and therefore insecure.
[ obs. grannam for GRANDAM + -Y(2) ]