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

• alpha
• beginning
• birth
• commencement
• dawn
• day one
• genesis
• get-go
• git-go
• inception
• incipience
• incipiency
• kickoff
• launch
• morning
• nascence
• nascency
• onset
• outset
• start
• 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

Their study modelled alternative timelines—starting in 1950, 1990, and a pre-industrial baseline—and found that in every case, temperature and sea-level rise would be measurably lower today. —Felicia Jackson, Forbes.com, 14 May 2025

While some measures have been paused — including a Monday hold on additional tariffs for Chinese goods — many are now in effect, including a 10% baseline tariff on most countries. —Mike Winters, CNBC, 13 May 2025

Ten still loom over the court from behind the baselines, at the sporting complex once called the Foro Mussolini. —Charlie Eccleshare, New York Times, 12 May 2025

Trump also announced a 25 percent tariff on all steel and aluminum products coming into the U.S. By March, China's duties were raised by another 10 percent to a 20 percent baseline. —Kate Nalepinski, MSNBC Newsweek, 12 May 2025

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