baseline

noun

base·​line ˈbās-ˌlīn 

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

• beginning
• start
• onset
• inception
• alpha
• commencement
• launch
• threshold

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

After the ball plunged through the net, Brunson let out a roar, strutted across the baseline, and headbutted the padded backstop beneath the hoop. —Tom Kludt, Vanity Fair, 17 Feb. 2026

Under the current baseline, federal debt is set to surpass the all-time record of 106% of GDP—set in the aftermath of World War II—by fiscal year 2030. —Nick Lichtenberg, Fortune, 17 Feb. 2026

While many Michigan schools have already adopted their own cellphone policies, the new law will create baseline regulations for all public school districts, where officials could still consider stricter rules. —Jordyn Hermani, Los Angeles Times, 17 Feb. 2026

The league has found the baseline for new iterations of its marquee event moving forward. —Kristian Winfield, New York Daily News, 16 Feb. 2026

Word History

First Known Use

circa 1556, in the meaning defined at sense 1

Rhymes for baseline

• acridine
• alkaline
• andesine
• anodyne
• anticline
• arginine
• asinine
• atropine
• benzidine
• borderline
• byzantine
• calamine

Kids Definition

baseline

noun

base·​line ˈbās-ˌlīn 

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 

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