Canto 3 -
Araṇya-kāṇḍa
Chapter 69: Rāma and Lakṣmaṇa Meet Kabandha
Text 3.69.27

आसेदतुस्ततस्तत्र तावुभौ प्रमुखे स्थितम्।
विवृद्धमशिरोग्रीवं कबन्धमुदरेमुखम्॥

āsedatus tatas tatra tāv ubhau pramukhe sthitam
vivṛddham aśiro-grīvaṁ kabandham udare mukham

āsedatuḥ = approached; tataḥ = then; tatra = there; tau ubhau = both of Them; pramukhe = in front [of Them]; sthitam = who stood; vivṛddham = he was tall; aśiraḥ-grīvam = without a head or neck; kabandham = Kabandha; udare-mukham = and his face was in his belly.

Then both of Them approached Kabandha who stood in front [of Them] there. He was tall, without a head or neck, and his face was in his belly.

He lacked a head or neck, that is, his head or neck could not be seen. Therefore, he had the appropriate name Kabandha.1 

1 Kabandha literally means “a headless trunk.”