a real or imaginary line passing through the center of something and dividing it into two equal parts
centerline in American English
(ˈsentərˌlain)
noun
1.
any line that bisects a plane figure
the centerline of a building plan
2.
a line along the center of a road or highway dividing it into separate sections for traffic moving in opposite directions
3. Radio
the perpendicular bisector of the line connecting two radio transmitters
Also: center line
Word origin
[1800–10; center + line1]This word is first recorded in the period 1800–10. Other words that entered Englishat around the same time include: hike, isolate, jumbo, sodium, unprofessional