baseline

American  

[beys-lahyn] / ˈbeɪsˌlaɪn /

noun

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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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

“In our view, a correction was inevitable and ultimately healthy if this bull market is going to extend into year-end, which remains our baseline with an 8,000 S&P 500 target.”

From MarketWatch • Jun. 8, 2026

Zverev's ability to inject more pace in the baseline exchanges helped him decisively break in the 10th game of the third set, but tension took hold in a dramatic fourth set.

From BBC • Jun. 7, 2026

In its baseline forecast, Fitch expects the U.S. economy to grow 1.9% and the eurozone economy 0.9%, both lower than previously projected.

From The Wall Street Journal • Jun. 5, 2026

It shows revenue stability, proves customer satisfaction, and provides a baseline for company valuation.

From Barron's • Jun. 4, 2026

He tried to cut around the baseline looking for a backdoor play or maybe to post me up low.

From "Slam!" by Walter Dean Myers

Related Words

• control
• criterion
• guideline
• measure
• standard