Shia US/ˈʃiʌ/ uncommon noun 1. one of the two main branches of orthodox Islam; mainly in Iran SynonymsShiahShiah Islamthe Shiites Related words Word family ShiahShiah IslamshiatsuShia Muslim Broader terms sect Parts Islam Part of Shiite WordNet 2.1 (Princeton University). CMU Pronouncing Dictionary. WordNet 2.1 Copyright Princeton University. All rights reserved.