What is the term for a trading curb that halts trading on the NYSE after a 7% drop?

A trading curb that halts NYSE trading after a 7% market decline is called a circuit breaker.

The modern U.S. system uses percentage-based market-wide circuit breakers tied to the S&P 500’s decline from the previous close. A 7% fall is Level 1 and normally triggers a 15-minute trading halt when reached before 3:25 p.m. A 13% decline is Level 2, while a 20% decline is Level 3 and closes the market for the rest of the day.

Circuit breakers were created after the 1987 crash, when disorderly selling and overloaded trading systems made it difficult for buyers and sellers to transact normally. The pause is designed to give market participants time to assess news, orders, and liquidity.

A trading halt is a broader phrase for any temporary suspension of trading, including halts affecting one security. Limit Up–Limit Down is a separate system for extreme price movements in individual securities, so it is not the best answer to this market-wide question.