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

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Etymology

Origin of baseline

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

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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

"As the majority of this group began arriving from 2022 onwards, this is currently set to begin in 2027. We consult here on a separate baseline qualifying period, of 15 years, for this group."

From BBC ● Nov. 2, 2026

Georgia also stands to benefit because the state keeps savings from its previous federal baseline spending, which it can use to finance reinsurance to lower premiums in high-cost rural areas.

From The Wall Street Journal ● Nov. 1, 2026

It produced both a baseline floor and a potential upper ceiling for snake envenomings and fatalities.

From Science Daily ● Oct. 30, 2026

We have a running tab at Boston Children’s Hospital, and a baseline level of uncertainty about her health.

From Slate ● Oct. 28, 2026

He started nearly at the opposite baseline and ran with the ball to center court, then flung the ball and himself.

From "Millionaires for the Month" by Stacey McAnulty

Economists say that consumers generally focus more on the cumulative effect of years of steadily rising prices than on individual monthly metrics, and that it takes years for consumers to adjust to new price baselines.

From The Wall Street Journal ● Oct. 8, 2026

The “2026 Postseason” decals had been freshly painted up the baselines that afternoon.

From Los Angeles Times ● Oct. 2, 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

"The Human Flatus Atlas will establish objective baselines for gut microbial fermentation, which is essential groundwork for evaluating how dietary, probiotic or prebiotic interventions change microbiome activity."

From Science Daily ● Mar. 14, 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

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Related Words

• control
• criterion
• guideline
• measure
• standard

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