Sambhar is normally made in every South Indian house daily. It is also prepared by North Indians communities along with Dosa, Idli, uttappam etc. It is a combination of certain vegetables boiled in tamarind pulp and tur dal boiled and mixed in it. the masalas can be freshly ground or sambar powder you can use it. It goes well with Idli, Dosa, Uttappa and rice also.
Normally, I make sambhar with the sambar powder without coconut and tamarind as we do not consume both at all. For arachuvitta sambar, the masala is freshly ground along with coconut and added to sambar.