The primary and smallest physically perceivable unit of measurement of length was aṅgula (angula) or aṅguli (anguli) — tāsām āyāma-viṣkaṃbhān sanniveśāntarāṇi ca/cakrustadā mahāprajñaṃ mitvā mitvāntano’ṅgulaiḥ.
When the sunrays enter a dark room through a narrow chink in the window one can see thousands of dust particles floating around in the luminescent stream of sun light, and one such dust particle is called trasareṇu (trasarenu). If we accumulate eight such trasareṇu the resultant measurement is called valāgra (valagra). Eight valāgra make one likṣā (liksha); eight likṣā make one yūkā (yuka); eight yūkā make one yava; and eight yava make one aṅgula or aṅguli.