Background Map
Commonly used to refer to a home-made map (such as my MN or MI maps) to denote the fact that they're "real" GPS maps and not just tracklogs. In other words, they show up on the GPS just like a commercial map package, and not just tracks drawn on top.

Basemap
A very basic map that is installed on a GPSr by default. Also commonly used to refer to home-made installable GPS maps (such as my MN or MI maps) to distinguish them from simple tracklogs.

GPS
Stands for Global Positioning System. The system is a series of satellites and a receiver that can determine your approximate position by measuring the strength of the signal from several visibile satellites with known positions. GPS also commonly used to refer to a GPS receiver, which, while technically incorrect (similar to calling a DVD player a DVD), is generally acceptable.

GPSr
A GPS (Global Positioning System) receiver. In other words, it's the little device with the screen that tells you where you are.

GPX File
A standard file format for storing GPS data, such as tracklogs and waypoints.

Latitude
Number of degrees North or South of the equator.

Longitude
Number of degrees East or West of the prime meridian.

Mapsource
Garmin's software for organizing and transferring maps, tracklogs, waypoints, routes, etc., to and from a GPSr.

Point Of Interest
Landmarks such as hotels, restaurants, stores, gas statiions, etc., that are displayed on a GPS map and often searchable from within a GPSr's menus.

Route
An ordered series of waypoints for navigation. A GPS will give you navigation instructions along a route.

Snowmobile
A vehicle designed to travel on snow and cost lots of money.

Track
See Tracklog.

Tracklog
A series of points that make up a path. When you set your GPSr to record a breakcrumb trail of a snowmobile ride, you're making a tracklog.

TYP File
A method of modifying the look of Garmin map features.

Transparent Map
A map with no background that can be overlayed on another map. For instance, a transparent snowmobile trail map could show snowmobile trails on top of Garmin's Topo series.

Waypoint
A single point on a map that marks a location of interest.

WAAS
Stands for Wide Area Augmentation System. A WAAS-capable GPSr can receive signals from several ground stations in addition to satellites for greater accurcy. Usually uses more battery power and only works when you have a clear view of the horizon.