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

• alpha
• beginning
• birth
• commencement
• dawn
• day one
• genesis
• get-go
• git-go
• inception
• incipience
• incipiency
• kickoff
• launch
• morning
• nascence
• nascency
• onset
• outset
• start
• 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

When comparing the Danish study to the United States population, keep in mind that breast cancer screening in the US starts at age 40, with many insurance companies covering baseline mammograms at age 35. —Dominique Fluker, Essence, 28 Oct. 2024

One potentially significant difference: The younger women donating eggs have much higher baseline fertility than the older women going through IVF. —Emma Whitford, Forbes, 26 Oct. 2024

Use a price tracking tool well in advance of your trip to determine a baseline price for your ideal route. —Stefanie Waldek, Travel + Leisure, 26 Oct. 2024

Her description appears to contradict the baseline characteristics of the 95 study participants, which were published in 2022. —Brenda Goodman, CNN, 25 Oct. 2024

Word History

First Known Use

circa 1556, in the meaning defined at sense 1

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