Longitude lines run north to south of the Earth.
Latitude lines run east to west of the Earth.
(You can remember which is which by thinking of Santa Clause: LONGatude is up and down and FATatitude is across.)
latitude?
lines of latitude
Each 'meridian' is a line of constant longitude.
Latitude.
Every meridian of longitude is perpendicular to every parallel of latitude, and every parallel of latitude is perpendicular to every meridian of longitude.
Latitude and longitude
The lines that intercept latitude lines are lines of longitude.
Lines of Longitude
Every parallel of latitude crosses every meridian of longitude.
Longitude lines go vertically and latitude lines go horizontally.
Lines of latitude and longitude allows any position on the Earth to be plotted.
Latitude is side to side and longitude is up and down.