breastfeeding [AS, braest + ME, feden] , 1. suckling or nursing, giving a baby milk from the breast. Breastfeeding encourages postpartum uterine involution and slows the natural return of the menses. The World Health Organization recommends continued breastfeeding up to 2 years of age or beyond. Also called nursing. 2. taking milk from the breast. See also breast milk, lactation.