Wiktionary
n. A device used by a lactation woman to extract milk from her breasts (typically for short-term storage).
Wikipedia
A breast pump is a mechanical device that extracts milk from the breasts of a lactating woman. Breast pumps may be manual devices powered by hand or foot movements or electrical devices powered by electricity or batteries.
Usage examples of "breast pump".
The recommended preparation for prospective adoptive mothers is to use a breast pump every few hours to simulate sucking, beginning about a month before the expected delivery of the birth mother.
Sapirstein showed her how to use a rubber-bulbed breast pump, like a glass auto horn.
With a sigh of resignation, I reached for the breast pump, an ungainly and ridiculous-looking rubber contraption.
Now it was a demonstration of a convenient electric breast pump to store up natural mother's milk for those times when you just can't be with baby.