別腹

Etymology 1
Compound of.

Noun

 * 1) “separate stomach”: appetite or ability to continue eating after a meal: a hollow leg
 * 2) “separate belly”: in reference to siblings who share the same father but have different mothers
 * 1) “separate belly”: in reference to siblings who share the same father but have different mothers

Usage notes

 * This sense often extends to the appetite for or capacity to eat a particular type of food, such as sweets.

Etymology 2
From compound.

Noun

 * 1) “separate belly”: in reference to siblings who share the same father but have different mothers