Definition of vertical line
: a line perpendicular to a surface or to another line considered as a base: such as a : a line perpendicular to the horizon b : a line parallel to the sides of a page or sheet as distinguished from a horizontal line c : the direction of a plumb line : a line normal to the surface of still water
Start your free trial today and get unlimited access to America's largest dictionary, with:
- More than 250,000 words that aren't in our free dictionary
- Expanded definitions, etymologies, and usage notes
- Advanced search features
- Ad free!
Seen and Heard
What made you want to look up vertical line? Please tell us where you read or heard it (including the quote, if possible).