what is a "wet nurse" ?要有埋語源。

A wet nurse (乳母/奶媽) is a woman hired to breast feed and care for another's child.[1] Wet nurses are hired when the mother is unable or chooses not to nurse the child herself. The practice of using wet nurses is ancient and common to many cultures. It has been linked to social class, where the aristocracy, nobility or upper classes had their children wet-nursed in the hope of becoming pregnant again quickly. Ancient historyMany cultures feature myths involving superhuman, supernatural, human and in some instances animal wet-nurses. The ancient Romans believed their collective origin to be from Romulus and Remus, who were breast-fed by the she-wolf, Lupa,