World Geodetic System 1984 — the global standard coordinate reference system used by GPS and most web mapping applications.
WGS84 (EPSG:4326) defines the Earth's shape and the coordinate system used to describe positions on it. GPS receivers output coordinates in WGS84. Google Maps, OpenStreetMap, and most web mapping services use WGS84 or the closely related Web Mercator projection. In Canada, WGS84 and NAD83 are nearly identical for most practical purposes.