noun.
The pilgrimage to Mecca made by pious Muslims; one of the five pillars
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
noun.
the fifth pillar of Islam is a pilgrimage to Mecca during the month of Dhu al-Hijja; at least once in a lifetime a Muslim is expected to make a religious journey to Mecca and the Kaaba
Word Usage
"This annual pilgrimage, one of the largest religious gatherings on earth, lasting up to five days, is known as the hajj."