to nurse at the breast: to draw milk as an infant, or to give it as a mother or nurse
This single word covers both sides of one act: the baby who takes milk at the breast and the mother or hired nurse who gives it. Hebrew names the whole scene of nursing with one root, so the same word swings between the child and the woman depending on the grammar. English has to split that into different words (suck, give suck, suckle, nurse), but in Hebrew it is all one picture.
From that root come two everyday nouns for the people in the scene. One is the nursing child, the infant still at the breast, which the Bible pairs again and again with the very old and the very small to name the most vulnerable people in a town. The other is the nurse or nursing mother, the woman who suckles a child, whether the child's own mother or a woman hired for the task.
The word also stretches into a picture of drawing in wealth and plenty. Israel is said to suck honey from the rock, to suck the abundance hidden in the seas and sand, and one day to suck the milk of nations. In these lines the language of an infant feeding at the breast becomes a way of speaking about being richly nourished and provided for.