What is a pool2 in crypto?

A pool2 is where a crypto project (such as Uniswap, Aave, etc) offer speculators the option of providing liquidity for their token, in exchange for token rewards. I.e. you deposit XYZ/ETH LP from sushi into this staking contract, we pay you X% APR, paid in XYZ token.

For more information, see this article