Garlic knots are a type of garlic bread found primarily in pizzerias around New York City and the surrounding regions. They were developed in 1973 in Ozone Park Queens, as a way of making use of pizza dough scraps, and very quickly caught on.
The dough is rolled and then pulled into small, tight overhand knots, and pre-baked in a pizza oven (authentically, at temperatures of 700°F or higher). The knots are then dipped in or generously brushed with a mix of oil, parmesan cheese, and crushed garlic; variations can include finely chopped parsley, dried oregano, or black pepper. Before serving, garlic knots are baked a second time, and may be accompanied with marinara sauce.
As they're traditionally a way to make use of scraps, garlic knots tend to be the least expensive item on a pizzeria menu, often provided as complimentary with larger orders.