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 Green Wave overcame a six-point deficit in the fourth quarter and forced OT on Younger’s baseline drive with 20 seconds remaining and Sauls’ layup with 10 seconds left. —Patrick Z. McGavin, Chicago Tribune, 3 Mar. 2026

The 7-foot-1 and 300-something Shaq sat baseline, tucked toward the end of the Hornets bench. —Joe Davidson, Sacbee.com, 3 Mar. 2026

Down 125-122 with 90 seconds to go, Denver went to flat spacing along the baseline and allowed Murray to dance in isolation for a tough midrange jumper. —Bennett Durando, Denver Post, 3 Mar. 2026

Led Zeppelin’s streams also maintained a new baseline average of 38 million per week through January, which is 16% over the previous period. —Cerys Davies, Los Angeles Times, 3 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