noun, often attributive
base·​line | \ ˈbās-ˌlīn How to pronounce baseline (audio) \

Definition of baseline

1 : a line serving as a basis especially : one of known measure or position used (as in surveying or navigation) to calculate or locate something
2a : either of the lines on a baseball field that lead from home plate to first base and third base and are extended into the outfield as foul lines
b : basepath
3 : a boundary line at either end of a court (as in tennis or basketball)
4 : a usually initial set of critical observations or data used for comparison or a control
5 : a starting point the baseline of this discussion

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Examples of baseline in a Sentence

The experiment is meant only to provide a baseline for other studies. any year or event we use as the baseline for the Renaissance is going to be at least somewhat arbitrary
Recent Examples on the Web This, however, merely piled extra dysfunction onto a baseline of dysfunction that all human sinuses share. New York Times, 3 May 2022 Every district in the city will provide an additional third-grade Gifted and Talented entry point, amounting to a baseline of one program in every district and a total of 1,000 seats. Kristina Sgueglia And Dalila-johari Paul, CNN, 14 Apr. 2022 For Newport Fancher, this means living with a consistent baseline of pain that gets somewhat better or much worse with certain triggers—one of the most significant being weather. Natasha Lavender, SELF, 11 Mar. 2022 Early reports had begun rolling in about mass layoffs, which seemed poised to drive up the rate of uninsurance from the already high baseline of around 30 million people. Natalie Shure, The New Republic, 8 Mar. 2022 The evidence collected created a baseline of information about Mexican Americans. Elaine Ayala, San Antonio Express-News, 7 Mar. 2022 So the water from a storm—hurricane or otherwise—piles on the higher baseline of sea level rise, overwhelming storm water systems. Matt Simon, Wired, 24 Feb. 2022 As recently as 2008, only 9 percent of hospitals had an electronic records system that met a federal baseline of functionality, according to a government analysis. NBC News, 10 Feb. 2022 To start, researchers had to determine a baseline of how current activity levels affected death rates. Ashley Abramson,, 28 Jan. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'baseline.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of baseline

circa 1556, in the meaning defined at sense 1

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Time Traveler for baseline

Time Traveler

The first known use of baseline was circa 1556

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Dictionary Entries Near baseline

baselevel plain



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Statistics for baseline

Last Updated

19 May 2022

Cite this Entry

“Baseline.” Dictionary, Merriam-Webster, Accessed 23 May. 2022.

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More Definitions for baseline


base·​line | \ ˈbā-ˌslīn How to pronounce baseline (audio) \

Medical Definition of baseline

: a set of critical observations or data used for comparison or a control

More from Merriam-Webster on baseline

Nglish: Translation of baseline for Spanish Speakers

Britannica English: Translation of baseline for Arabic Speakers


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