1.
slight hunger; small appetite; peckishness
A mild feeling of hunger between meals, not enough to warrant a full meal but enough to want a small snack.
小腹が空いた。
I'm a little hungry.
Literally 'small belly' (小 small + 腹 belly/stomach). Used almost exclusively in the expression 小腹が空く (to be slightly hungry). The 小 prefix softens the degree, distinguishing it from full-on hunger.
Common collocations
Usage
This word is strongly associated with snacking culture. It describes the feeling that leads you to eat a light snack (軽食) or buy something from a convenience store between meals. Very common in advertising for snack foods.