Latitude is "imaginary" lines that run around the earth PARALLEL to the equator. They represent degree from the equator to the poles. For example, the equator is also the zero degree latitude line; the north pole is at 90 degrees or at 90 degrees North Latitude; the south pole is at -90 degrees or 90 degrees South Latitude. Everything in between can be referenced to these values.
Longitude lines are imaginary lines running from the north pole to the south pole. These lines are farther apart at the equator and get closer as they approach the poles where they converge (or come together). Longitudes are usually referenced from Greenwich, England where it has been established as Zero Degrees longitude. There are 360 degrees (i.e., a complete circle) around the earth, but generally is referenced as 180 degrees East of Greenwich (or +180 degrees) or 180 degrees West of Greenwich (or -180 degrees).
The degrees are further divided in minutes and seconds, so that there are 60 seconds in a minute and 60 minutes in a degree. So one might reference a spot as being 35 degrees, 10 minutes, 22 seconds North (often written as 35 deg 10' 22") and 96 degrees, 6 minutes, 30 seconds West (96 deg 6' 30").
Or those same numbers might be should strictly as decimal degrees such as (using the same example): 35.17278N, 96.10833W.