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

The tests allow the patient to get a baseline of their current condition and give the ability for people to be proactive with their heart health instead of reactive. —Ryan Canfield, FOXNews.com, 26 Apr. 2026

Bane started the afternoon with a reverse layup down the baseline on the opening possession and quickly raced up eight first-quarter points. —Jason Beede, The Orlando Sentinel, 25 Apr. 2026

Sengun’s attempt at a game-winner when he got stood up by Jaxson Hayes on a turnaround baseline floater wasn’t the play the Rockets drew up, Udoka said. —Los Angeles Times, 25 Apr. 2026

Moments after that, Harper drove for a baseline dunk over a closing Robert Williams III that had even Wembanyama in awe on the bench. —Jeff McDonald, San Antonio Express-News, 25 Apr. 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