Natyashastra
क्षामं हास्येऽथ रुदिते निःश्वासे जृम्भने भवेत् । व्याधिते तपसि श्रान्ते क्षुधार्ते खल्वमिष्यते ॥ २४४॥
The thin belly (Kṣāma) is used in laughter, weeping, exhaling, yawning, in sickness, penance, weariness, and hunger. The depressed belly (Khalva) is used in these contexts.
english translation
kSAmaM hAsye'tha rudite niHzvAse jRmbhane bhavet । vyAdhite tapasi zrAnte kSudhArte khalvamiSyate ॥ 244॥
hk transliteration by Sanscript