Lexicons, Nirukta & Buddhist · c. 5th century BCE; the Nighaṇṭu word-list older still
ऋक्षाः स्तृभिरिति नक्षत्राणाम् । ... स्तृभिस्तीर्णानीव ख्यायन्ते । ... पश्यन्तो द्यामिव स्तृभिः ।
'Rksāh and strbhih are (synonyms) of stars.' ... 'Strbhih (stars) appear to be scattered (in the sky).' ... 'Looking at the sky with stars, as it were.' — Lakshman Sarup (1921)
The oldest Sanskrit word for 'stars', and the one the Nighaṇṭu pairs with ṛkṣāḥ. Yāska derives it from stṛ 'to scatter/strew' — 'they appear as if strewn'. Cognate with Greek astēr, Latin stella, English star. Attested at RV 4.7.3, quoted by Yāska.
Nirukta 3.20 (on Nighaṇṭu 3) · text · translation