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

Jenkins got revenge by hitting a midrange baseline jumper over Reaves to put the Pistons back in front with 25 seconds left. —Los Angeles Times, 24 Mar. 2026

But at the baseline, the Yankees appear poised to be a contender once again. —Peter Sblendorio, New York Daily News, 23 Mar. 2026

Rather than attack the rim, Lee opted to dribble toward the baseline and attempted a wraparound pass to Haugh, who couldn’t control the ball as time expired. —Edgar Thompson, The Orlando Sentinel, 23 Mar. 2026

In those days, southern white liberals seemed to be a growing category (from a small baseline), and one that was available to me personally. —Adam Kirsch, The Atlantic, 23 Mar. 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