LP burn and LP lock
Also: LP burn, LP lock, burned liquidity, locked liquidity
When someone adds liquidity to a DEX pool, they receive LP tokens, which work like a receipt: whoever holds them can withdraw that share of the pool. If a memecoin's creator keeps the LP tokens, they can pull the SOL or ETH out of the pool at any moment and leave holders with a worthless token. That is the classic rug pull.
LP burn means sending the LP tokens to an address nobody can recover them from, so the liquidity stays in the pool forever. Some launchpads do this automatically at migration. LP lock means placing the LP tokens in a locking contract for a set period, after which the owner can withdraw them again. Burned liquidity does not, however, protect you from the creator and large wallets selling their tokens.