mochi given to new mothers; lactation mochi
A traditional custom: mochi received from one's parents after childbirth, traditionally eaten in miso soup and believed to improve lactation. This is a culturally specific term with no direct English equivalent.
出産後、実家から汁の餅が届いた。
After giving birth, I received shiru-no-mochi from my parents' home.
汁の餅は味噌汁に入れて食べる習慣がある。
There is a custom of eating shiru-no-mochi by putting it in miso soup.
Compound of 汁 (shiru, 'soup') + の (no, possessive particle) + 餅 (mochi, 'rice cake'), referring to mochi eaten in soup as part of a postpartum tradition. The exact historical origin of the custom is uncertain.