National Instant Criminal Background Check System [NICS] Law and Legal Definition

The National Instant Criminal Background Check System (NICS) is a checkout system for determining the eligibility of a purchaser to purchase firearms in the U.S. The NICS is used by the Federal Firearms License (FFL) holders for determining whether it is legal to sell a firearm to a prospective purchaser. The NICS also helps in determining whether a buyer is prohibited from buying a firearm under the Gun Control Act of 1968.