Urad, also referred to as urad dal, urd bean, urd, urid, black matpe bean, black gram, black lentil, or white lentil (Vigna mungo) is a bean grown in southern Asia. It is largely used to make dal from the whole or split, dehusked seeds. The bean is boiled and eaten whole or after splitting into dal; prepared like this it has an unusual texture. Ground into flour or paste, it is also extensively used in culinary preparation like dosa, idly, vada and Papad. When used this way, the white lentils are usually used. The white lentils are called "ulundhu" (உளுந்து) in Tamil.
It is very nutritious and is recommended for diabetics, as are other pulses. It is very popular in Punjabi cuisine of India and Pakistan where it is known as "maanh".The product sold as "black lentil" is usually the whole urad bean or urad dal. The product sold as "white lentil" is the same lentil with the black skin removed. This lentil or dhall is also available in all Indian stores nicely packed. The packet here in the picture is whole white urad dhall and the other two pictures are whole black urad dhall and white split urad dhall. For seasoning, split urad dhall will be mostly used and for making Idly batter or Vada Batter or Bonda batter ,(the consistency of batter for both vada and bonda is somewhat same; Bonda batter will be little bit thicker than Vada batter) whole urad will be used. For making Adai batter, Black urad dhall will be used.