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 विदर
विदरvidara1 Breaking, bursting, rending.
1 Breaking, bursting, rending.
A cavity, a slit; अदूरजाग्रद्विदरप्रणालीरेखाName8.38.