baseline

noun

base·​line ˈbās-ˌlīn How to pronounce baseline (audio)
Synonyms of baseline
often attributive
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
2
a
: 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

Synonyms of baseline

Relevance
See All Synonyms & Antonyms in Thesaurus

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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The pair hunched over a laptop, studying the intricacies of Miller’s approach to shutting off the baseline on defense. — Julia Poe, Chicago Tribune, 28 Oct. 2026 That said, an annual review should generally be viewed as a baseline rather than a rule that requires you to wait 12 months between updates. — Angelica Leicht, CBS News, 27 Oct. 2026 Netanyahu has changed the baseline of how Israelis think about their country’s security and turned his own uncompromising positions into an institutionalized reality. — Dalia Dassa Kaye, Foreign Affairs, 27 Oct. 2026 Total water levels this week in Los Angeles, Orange and San Diego counties could reach more than 8 feet above the baseline, which is defined as the average daily lowest water level observed between 1983 and 2001. — Hannah Fry, Los Angeles Times, 26 Oct. 2026 See All Example Sentences for baseline

Word History

First Known Use

circa 1556, in the meaning defined at sense 1

Time Traveler
The first known use of baseline was circa 1556

Rhymes for baseline

See All Rhymes for baseline

Browse Nearby Words

baselevel plain
baseline
baseliner
See all Nearby Words

Cite this Entry

“Baseline.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/baseline. Accessed 28 Oct. 2026.

Copy Citation

Kids Definition

baseline

noun
base·​line ˈbās-ˌlīn How to pronounce baseline (audio)
1
: a line used as a base
2
a
: either of two straight lines on a baseball field leading from home plate to first base and third base and extending into the outfield
b
: base path

Medical Definition

baseline

noun
base·​line ˈbā-ˌslīn How to pronounce baseline (audio)
: a set of critical observations or data used for comparison or a control
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Last Updated: - Updated example sentences

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of grotesque

See Definitions and Examples »

Popular in Grammar & Usage

See More

How to Use 'Who' vs. 'Whom'

Merriam-Webster’s Great Big List of Words You Love to Hate

'Affect' vs. 'Effect'

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?
See More

Popular in Wordplay

See More

The Longest Long Words List

9 Words That Sound Like Insults But Aren't

12 Lovely and Unusual Words for the Natural World

Why do we 'bury the lede?'

'Za' and 9 Other Words to Help You Win at SCRABBLE
See More

Popular

See More

How to Use 'Who' vs. 'Whom'

The Longest Long Words List

9 Words That Sound Like Insults But Aren't
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
different halloween monsters in silhouette
A Monstrous Vocab Quiz Words That Go Bump in the Night
See All