MAM'MIFER, noun [Latin mamma, the breast, and fero, to bear.] An animal which has breasts for nourishing its young. The mammifers have a double system of circulation, red and warm blood; the fetus is nourished in the matrix by means of one or more placentas, and the young by milk secreted by the breasts.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI