Mercator projection Syllabification: (Mer·ca·tor pro·jec·tion)Pronunciation: /mərˈkātər/ (also Mercator's projection)Definition of Mercator projection noun a projection of a map of the world onto a cylinder in such a way that all the parallels of latitude have the same length as the equator, used especially for marine charts and certain climatological maps. Mercator projection in other Oxford dictionaries Definition of Mercator projection in the British & World English dictionary