Definition of national committee in US English:

national committee

noun

  • 1A committee, usually invested with a number of administrative powers, intended to represent the members of a particular body, organization, or interest group nationwide, or to represent the interests of a nation in an international context.

  • 2US Politics. The executive committee of a political party, selected by the national convention, and with powers to nominate candidates for office, oversee the planning of campaigns, etc.

Origin

Early 19th century. From national + committee.