Definition of Nipple shield
Nipple shield: A cap or dome, usually made today of plastic (formerly, rubber), placed over the nipple and areola during nursing to permit the flow of milk, provide a larger surface for the baby to latch onto, and protect the breast if it is sore. However, because a nipple shield may reduce the stimulation needed to sustain lactation and may engender other problems, a nipple shield should only be used under professional care.