primary election

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A preliminary election in which voters nominate party candidates for office.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun politics A preliminary election to select a political candidate of a political party.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a preliminary election where delegates or nominees are chosen