The Relay Chain is the central chain of the Polkadot network. All validators of Polkadot are staked on the Relay Chain.
The Parachains are parallel chains that connect to the Relay chain and are maintained by their validators, called collators.
The Bridges are special blockchains that allow Parachains to connect to and communicate with external networks like Ethereum and Bitcoin.
Polkadot uses DOT tokens for operating on its network. DOT serves multiple purposes such as:
Governance: where participants can manage protocol updates and fixes.
Staking: where the tokens are staked to ensure the network remains secure, as good validators are rewarded, and bad actors lose their stake.
Bonding: where new parachains are supported by bonding tokens.
Fees: for ferrying messages across parachains.
Based on Polkadot’s first stakeholder vote, all DOT tokens will be redenominated by a factor of 100 at block 1,248,328, estimated to occur at 2020/08/21 4:40 PM (UTC). To support the redenomination plan, all DOT deposits made to Binance after block 1,205,128 will be multiplied by a coefficient of 100. For example, if a user deposits 10 DOT, he/she will be credited with 1,000 DOT to his/her account.