[ beys-lahyn ]
See synonyms for baseline on
nounAlso base line .
  1. Baseball. the area between bases within which a base runner must keep when running from one base to another.

  2. Tennis. the line at each end of a tennis court, parallel to the net, that marks the in-bounds limit of play.

  1. (in perspective drawing) a horizontal line in the immediate foreground formed by the intersection of the ground plane and the picture plane.

  2. a basic standard or level; guideline: to establish a baseline for future studies.

  3. a specific value or values that can serve as a comparison or control.

  4. Typography. the imaginary line on which the bottoms of primary letters align.

  5. Surveying. See under triangulation (def. 1).

  6. Electronics. a horizontal or vertical line formed on the face of a cathode-ray tube by the sweep of the scanning dot.

  7. Naval Architecture. a line on the body plan or sheer plan of a hull, representing a horizontal reference plane for vertical dimensions.

  1. basic or essential.

Origin of baseline

First recorded in 1740–50; base1 + line1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use baseline in a sentence

  • But General Lee abandoned the salient after dark, and put his whole force in the base line.

    Historic Fredericksburg | John T. Goolrick
  • A base line permanently fixed on the ship is the one side of a triangle required.

    Steam Steel and Electricity | James W. Steele
  • It was on the base line and 15 feet north of the copper find before described.

    The Swastika | Thomas Wilson
  • Webb set up the theodolite while Hurley and I paced out a half-mile base-line to find out the intervening distance.

    The Home of the Blizzard | Douglas Mawson
  • Every circle has 360 degrees, and when a certain degree is mentioned, it means a certain angle from what is called a base line.

British Dictionary definitions for baseline


/ (ˈbeɪsˌlaɪn) /

  1. surveying a measured line through a survey area from which triangulations are made

  2. an imaginary line, standard of value, etc, by which things are measured or compared

  1. a line at each end of a tennis court that marks the limit of play

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012