V. S. Apte, The Practical Sanskrit–English Dictionary. Look up any word of the Gita in Devanagari, IAST or Harvard-Kyoto, or browse the headwords letter by letter.
Entry अवस्तार
अवस्तारavastāraA curtain.
[अव-स्तॄ कर्मणि घञ्ParasmaipadaIII.3.12]
A curtain.
A covering; a screen or wall of cloth around a tent, hence concealing or fabricating. Compare Kau. Atmanepada 2.8.