Congress/ˈkɑːŋɡrəs/ Definition 1 of 3Pro Tip 1/3Government Context Used specifically to refer to formal legislative bodies in a government setting. Congress passed a new environmental law. Pro Tip 2/3Capitalized Usage Always capitalized when referring to a specific governmental body, such as the 'U.S. Congress'. She dreams of being elected to Congress. Pro Tip 3/3Not a Synonym 'Congress' and 'Senate' are not interchangeable; the Senate is part of Congress. He was confused about the difference between the Senate and Congress.