What is bid in Robinhood?

Could you please clarify what exactly is meant by the term 'bid' in the context of Robinhood, a popular trading platform for cryptocurrencies and other financial instruments? Specifically, how does the bid process work on Robinhood, and what role does it play in determining the prices of assets being traded on the platform? I'm particularly interested in understanding how the bidding mechanism differs, if at all, from other trading platforms or traditional financial markets.