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

By allowing wings like Kayla Thornton, Salaun and Kaila Charles to plant themselves on the baseline right outside of the paint, the driving lanes that Chicago enjoyed early were suddenly closed up. — Joseph Dycus, Mercury News, 22 Aug. 2026

Household cleaning, which is already foreign-dominated, is the most resilient, trailing baseline by just 4% in 2027 and 18% in 2030. — John Koetsier, Forbes.com, 22 Aug. 2026

These quick tests reveal fine detail, dimensional accuracy, and whether the printer is over- or under-exposed, providing a consistent baseline before evaluating more demanding real-world prints. — Michael Lydick, PC Magazine, 21 Aug. 2026

The veteran never runs too hot or too cold, instead providing the same baseline level of behavior every day. — Dan Hayes, New York Times, 20 Aug. 2026

Word History

First Known Use

circa 1556, in the meaning defined at sense 1

Rhymes for baseline

• alkaline
• andesine
• anodyne
• anticline
• arginine
• asinine
• benzidine
• borderline
• byzantine
• calamine
• caroline
• centerline

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