baseline

American  

[beys-lahyn] / ˈbeɪsˌlaɪn /

noun

• baselines
  plural

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.

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

4. a basic standard or level; guideline.

   to establish a baseline for future studies.

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

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

7. Surveying. triangulation1

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

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

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adjective

1. basic or essential.

baseline British  

/ ˈbeɪsˌlaɪn /

noun

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

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

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Other Word Forms

Noun Inflected Forms

• baselines
  plural

Etymology

Origin of baseline

First recorded in 1740–50; base ¹ + line ¹

Explanation

A baseline is an imaginary starting point or basis of comparison for something. To test how a class's performance improves over time, a researcher might begin with a baseline showing their current scores and grades. You're most likely to encounter baseline in technical or work-related writing, since it's mainly used to talk about comparing data. In land surveying, the baseline runs east and west, and all measurements and surveys are based on that main line. There's also a baseline in sports, marking certain boundaries on the field or court, including the route a baseball player takes rounding the bases toward home plate.

Example Sentences

See Examples For:

baseline baselines

"Treatments need to be tailored not just to the disease, but to how a patient's immune system operates at a baseline genetic level."

From Science Daily ● Aug. 20, 2026

If there were an extreme interest-rate shock, with rates doubling from the baseline scenario, payments would rise by $310,000.

From MarketWatch ● Aug. 18, 2026

“But eventually, your body starts remembering and you can build upon the baseline you develop by doing it repetitively.”

From Los Angeles Times ● Aug. 18, 2026

The team is currently using animals such as mice to establish baseline measurements of how fluid normally moves through the brain.

From Science Daily ● Aug. 13, 2026

To Dr. Greenfield, the true believer, it is a crucial piece of baseline evidence.

From "A Deadly Wandering: A Mystery, a Landmark Investigation, and the Astonishing Science of Attention in the Digital Age" by Matt Richtel

With shorter points, lower-bouncing balls and the risk of slippy baselines, the Wimbledon grass is not easy to master for those who have not grown up playing on it.

From BBC ● Jun. 28, 2026

While Major League Baseball has been sweating over pitch clocks, ghost runners and the Automated Ball-Strike Challenge System, the Savannah Bananas have been juggling, dancing, cartwheeling along the baselines and running to first on stilts.

From The Wall Street Journal ● Jun. 18, 2026

SK Hynix and Samsung have indicated rising capex as well, starting from higher baselines.

From Barron's ● Feb. 23, 2026

With apologies to the Surge’s editors, yes, we will be devoting an entry to the debate over “current law” versus “current policy” baselines.

From Slate ● Mar. 1, 2025

A. Ground strokes=All shots hit from the baselines off the bounce of the ball.

From The Art of Lawn Tennis by William (Bill) Tatem Tilden

Related Words

• control
• criterion
• guideline
• measure
• standard