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

But all the others sent Sabalenka scrambling, especially the last one that landed an inch from the baseline. —Matthew Futterman, The Athletic, 25 Jan. 2025

At her best, the 26-year-old’s powerful hitting from the baseline is borderline unstoppable, particularly on hard courts. —George Ramsay, CNN, 25 Jan. 2025

His cholesterol levels exceeded 1,000 mg per deciliter, far higher than his baseline level, between 210 and 300 mg. —Eduardo Cuevas, USA TODAY, 24 Jan. 2025

The Interior Department still needs to fill in the details, but that could potentially change the budget baseline for leasing expansion provisions in reconciliation. —Nick Sobczyk, Axios, 21 Jan. 2025

Word History

First Known Use

circa 1556, in the meaning defined at sense 1

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