E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The pilgrimage to Kaaba (temple of Mecca), which every Mahometan feels bound to make once at least before death. Those who neglect to do so might as well die Jews or Christians. These pilgrimages are made by caravans well supplied with water, and escorted by 1,400 armed men for defence against brigands. (Hebrew, hag, the festival of Jewish pilgrimages to Jerusalem.)
The green turban of the Mussulman distinguishes the devout hadji who has been to Mecca.Stephens: Egypt, vol. i. chap. xvii. p. 340.