Definition of "vada"

I bought a tea and a potato vada, and sat under a banyan tree to eat.

2008, Aravind Adiga, The White Tiger, Atlantic, published 2009, page 204

[…] "The mummers have got a slang of their own, which parties connected with the perfession[sic] generally use. […] "'Vada the glaze' is—Look at the window. […] "

1851, Henry Mayhew, “Our Street Folk”, in London Labour and the London Poor‎, volume 3, published 1861, Strolling Actors, page 139

You may have vada'd one of our tiny bijou masterpiecettes, heartface.

1967, Barry Took, Marty Feldman, “Gaslight Son of Flicker”, in Round the Horne, spoken by Sandy (Kenneth Williams)

Though she's a bimbo bit of hard, / she’s royal and tart. And girl, you know / vadaing her eek is always bona.

2015 October 12, Adam Lowe, “Poem of the week: Vada That”, in The Guardian‎