MECCA TREK is a term used to describe the journey of Muslims to the holy city of Mecca, Saudi Arabia. The two crossword solutions, HADJ and HAJJ, are both four-letter words that refer to the pilgrimage to Mecca. HADJ is an alternate spelling of HAJJ, which is the Arabic word for pilgrimage. Both words are used to describe the journey of Muslims to Mecca, which is one of the five pillars of Islam.