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.

---

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

---

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

Experts recommend treating the top of the range as your baseline target rather than as a pipe dream.

From MarketWatch ● Jul. 22, 2026

Future work that includes baseline imaging could provide stronger evidence of how brain structure changes over time.

From Science Daily ● Jul. 21, 2026

“Since high schools can vary so much, we really need a standardized baseline to measure students coming into the UC system.”

From Los Angeles Times ● Jul. 14, 2026

Tolo hopes to build a baseline picture of her health: She’s young and in the prime of her reproductive years, but her periods are characterized by severe pain that has long bedeviled her.

From The Wall Street Journal ● Jul. 13, 2026

The longer the baseline from which we make our two observations, the greater the parallax and the better we can measure the distance to remote objects.

From "Cosmos" by Carl Sagan

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

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

From Barron's ● Feb. 23, 2026

Buyers who come in with those baselines have an easier time sniffing out bad deals.

From The Wall Street Journal ● Feb. 2, 2026

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

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

Related Words

• control
• criterion
• guideline
• measure
• standard