Which term is synonymous with latitude lines?

Latitude lines, which run parallel to the equator, are often referred to as parallels. This terminology stems from their consistent distance apart and their horizontal alignment across the globe. Parallels indicate how far north or south a location is from the equator, which is defined as 0 degrees latitude.

The equator itself is a specific latitude line, marking the division between the Northern and Southern Hemispheres, but the term "equator" does not generally apply to all latitude lines. Longitude lines, in contrast, are referred to as meridians, which run from the North Pole to the South Pole and are not parallel but intersect at the poles. Thus, the term most synonymous with latitude lines is indeed parallels.