When completing a transaction on the Ethereum network you are required to pay a gas fee. These fees vary greatly depending on network congestion. The gas limit is the maximum total gas you are willing to pay for a specific transaction. When the Ethereum network is extremely busy, you may need to increase the gas limit you are willing to pay in order to guarantee the transaction goes through otherwise you might miss out on completing the transaction.
NFT Term
Gas Limit
Definition of Gas Limit from the NFTguild.com glossary.

