EIP stands for Ethereum Improvement Proposal. It is a document that proposes changes or improvements to the Ethereum network, such as new features or upgrades to existing ones. EIPs are the primary way that the Ethereum community collaborates and discusses changes to the protocol.

Anyone can create an EIP, and the process for proposing one is well-defined. EIPs go through several stages of review, including initial discussion, feedback, and revision. If an EIP is accepted, it is assigned a unique number and added to the official Ethereum repository.

EIPs have played a critical role in the development of Ethereum, enabling the community to work together to make the network more efficient, secure, and useful. Some notable EIPs include EIP-1559, which introduced a new fee structure for transactions, and EIP-721, which created the ERC-721 standard for non-fungible tokens (NFTs).