mammillae

During the biology class, the teacher pointed to a diagram and explained the structure of a mammilla.

用法提示：此处 mammilla 为名词单数，在句中作宾语，表示‘乳头’。

In many farm animals, the number of mammillae is related to how many babies they usually have.

用法提示：mammillae 是 mammilla 的复数形式，在句中作主语，指‘乳头’。

While breastfeeding, the mother felt a small lump near the mammilla and mentioned it to her doctor.

用法提示：句中 mammilla 为名词单数，表示‘乳头’，作介词 near 的宾语。