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

• beginning
• start
• onset
• alpha
• inception
• 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

Spyware has seen 147% increase, with February and March taking the biggest brunt as a 4 times multiplication of the baseline was observed. —Davey Winder, Forbes.com, 1 July 2025

Republicans have also cited Section 312 of Congressional Budget Act to argue that the final authority for determining baseline spending figures, and whether the tax portion of the bill violates Byrd, lies with Republican Senate Budget Committee Chair Lindsey Graham. —Hugh Cameron, MSNBC Newsweek, 30 June 2025

Republican senators say the Senate Budget Committee chairman has the authority to set the baseline for the preferred approach. —Kevin Freking, Chicago Tribune, 30 June 2025

Pay hikes in Alaska, D.C., and Oregon Alaska's baseline wage will rise by $1.09 to $13.00 an hour, which was approved via a ballot measure passed by voters. —Megan Cerullo, CBS News, 27 June 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