Latitude
The set of imaginary lines that are all parallel to the equator are the parallels of latitude. Whether they're horizontal or not depends on how you hold your map.
The equator!!!
The equator is a longer imaginary line.
The imaginary horizontal line that goes around the middle of the earth is called the equator.
They are parallel to the earth's equator. So if you consider the equator as being horizontal then they are horizontal.
The horizontal line that goes around the "waist" of the Earth is the Equator. The vertical line that goes vertically around the Earth, through the poles, is the Prime Meridian.
it is longitude
All lines of Latitude circle the earth, they are imaginary devices used on maps. Latitude is horizontal, think of the Horizon.
parallel lines, or lines of latitude.
Lines of latitude run east-west as circles parallel (or horizontal lines) to the equator. Latitude measures the angle in degrees north or south from the equator where the equator is located at 0 degrees.
Lines of latitude
The equator is an imaginary line.