A protocol and framework for creating Layer 2 blockchains and sidechains, both of which run parallel to and interact with the Ethereum network.  Introduced in 2017 as the Matic network, which was a plasma-based Layer 2 blockchain, the name was changed in 2021, but MATIC remained as the symbol for Polygon's native token.  Because of its Ethereum compatibility, more than a thousand decentralized apps (dApps) are compatible with Polygon chains.  See 
Layer 2 blockchain and 
Ethereum.
Polygon "secured chains" use a pool of professional validators, whereas Polygon "stand-alone chains" handle their own security and validator pool.  Polygon touts the following as "a suite of Ethereum scaling solutions."
Polygon Avail
A blockchain for storing transaction data that is separate from the smart contracts.  Avail decouples the data and execution layers.
Polygon Edge
A framework for public and private Ethereum-compatible blockchains that enables cross-chain asset transfer to and from Polygon.  Plug-ins are used to configure the networks.
Polygon ID
A digital ID system that uses zk-SNARK rollups (see 
zero-knowledge proof).
Polygon Miden
A Layer 2 blockchain that uses zk-STARK rollups.  The Miden virtual machine is said to be quantum secure.  See 
zero-knowledge proof and 
quantum secure.
Polygon Nightfall
A Layer 2 blockchain that uses optimistic rollups, which is a different proof method than zk-Rollups (see 
Optimism).  Nightfall is suggested for private NFT marketplaces, DAO voting and supply chain orchestration.
Polygon PoS
A plasma-based Layer 2 blockchain that uses the proof-of-stake (PoS) consensus mechanism.  See 
Layer 2 blockchain.
Polygon Supernets
A proof-of-stake (PoS) blockchain with an optional Layer 2.  See 
proof-of-stake algorithm.
Polygon Zero
A Layer 2 blockchain that takes advantage of all the computing power currently online.  Polygon Zero uses zk-Rollups and generates fast proofs.  See 
zero-knowledge proof.
Polygon zkEVM
An EVM-compatible Layer 2 blockchain that uses zk-STARK rollups and runs Ethereum smart contracts.  See 
zero-knowledge proof.