Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 2: Lord Brahmā Instructs Vālmīki
Text 1.2.4
स तु तीरं समासाद्य तमसाया मुनिस्तदा।
शिष्यमाह स्थितं पार्श्वे दृष्ट्वा तीर्थमकर्दमम्॥
sa tu tīraṁ samāsādya tamasāyā munis tadā
śiṣyam āha sthitaṁ pārśve dṛṣṭvā tīrtham akardamam
saḥ tu = the; tīram = [at] the bank of the river; samāsādya = arriving at; tamasāyāḥ = of Tamasā; muniḥ tadā = [the] sage; śiṣyam = [his] disciple; āha = [and] spoke; sthitam = standing; pārśve = nearby; dṛṣṭvā = noticed and; tīrtham = a sacred spot on the river; akardamam = was mudless.
Arriving at the bank of Tamasā, the sage noticed that a sacred spot on the river was mudless and spoke to his disciple standing nearby.
[5] tīrthaṁ mantrādy-upādhyāya-śāstreṣv ambuni pavane / pātropāyāvatāreṣu (Vaijayantī).
The word tīrtham refers to a sacred spot of a water body [5].