baseline

American  

[bays-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

There are some baseline things that need to happen in a system that’s working, and nothing is more baseline in a rule of law country than fact-finding.

From Slate ● Oct. 5, 2026

For adults who don’t have a primary-care physician, or who have one who doesn’t look at whole health, Neko offers a helpful baseline for those important years between high school graduation and Medicare.

From MarketWatch ● Oct. 5, 2026

At the beginning of the experiment, each participant lay quietly while the researchers recorded one minute of baseline BS using an electronic stethoscope and advanced signal-processing software.

From Science Daily ● Oct. 5, 2026

Overall, an average of 12 million barrels of oil per day passed through the strait over this period, compared with a pre-war baseline of 17 million.

From BBC ● Oct. 2, 2026

To establish her cognitive baseline that day, the researchers had her do some math problems and memory challenges.

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

Though grocery costs may decrease slightly once fuel costs stabilize, they are unlikely to return to prewar baselines as retailers adjust to higher prices, Vyas noted, pointing to sustained increases in food costs post-pandemic.

From Los Angeles Times ● Sep. 4, 2026

The alliance is also reviewing members’ production capacity to establish 2027 output baselines, which will determine future quotas, though the conflict in the Middle East has likely complicated the assessment.

From The Wall Street Journal ● Jul. 29, 2026

"Iraq's request may become part of the 2027 capacity review, where production baselines will be examined," he added.

From Barron's ● Jul. 5, 2026

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

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