(AP) — The Supplemental Nutrition Assistance Program, or SNAP, is a major piece of the U.S. social safety net used by nearly 42 million, or about 1 in 8 Americans, to help buy groceries.

Originally known as the food stamp program, it has existed since 1964, serving low-income people, many of whom have jobs but don’t make enough money to cover all the basic costs of living.

Public attention has focused on the program since President Donald Trump’s administration announced last week that it would freeze SNAP payments starting Nov. 1 in the midst of a monthlong federal government shutdown. The administration argued it wasn’t allowed to use a contingency fund with about $5 billion in it to help keep the program going. But on Friday, two federal judges ruled in separate challenges that the federal government must continue to fund SNAP, at least partially, using contingency funds. However, the federal government is expected to appeal, and the process to restart SNAP payments would likely take one to two weeks.

Who’s eligible? There are income limits based on family size, expenses and whether households include someone who is elderly or has a disability.

Most SNAP participants are families with children, and more than 1 in 3 include older adults or someone with a disability.