In simple means, A depository participant (DP) is an entity registered with SEBI under provisions. It acts as an agent between the Depositories (NSDL and CDSL in India) and investors.
The main role of DP is to maintain the ownership records of investors in a dematerialised form (Demat).
Stock Exchanges (BSE, NSE etc.,)
Depositories (CDSL and NSDL)
Depository Participants (Banks and NBFCs)