Layer 1 vs Layer 2
Plain English
Layer 1 is the main blockchain (like Solana, Ethereum, Bitcoin). Layer 2 are additional networks built on top to make things faster and cheaper. Think of Layer 1 as highways and Layer 2 as express lanes that reduce traffic on the main road.
Technical
Layer 1 (L1) refers to the base blockchain protocol with its own consensus mechanism and native token. Layer 2 (L2) solutions are secondary protocols built on top of L1 to improve scalability, reduce costs, and add functionality while inheriting L1 security. Examples: Ethereum (L1) with Polygon/Arbitrum (L2), Bitcoin (L1) with Lightning Network (L2).