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 सौत्र
सौत्रsautraa.(-त्री f.) [सूत्र-अण्]
(-त्रीFeminine) सूत्र-अण्
Belonging to or having a thread or string.
Belonging to, mentioned, occurring or declared in, a Sūtra quod vide, which see
Derived forms and compounds
-त्रः
A Brāhmaṇa.
An artificial root occurring in grammatical Sūtras which cannot be conjugated like a regular verb, but is used only to form derivative words.