longitudinal
adjective
lon·gi·tu·di·nal
ˌlän-jə-ˈtüd-nəl 
-ˈtyüd-,
-ˈt(y)ü-dᵊn-əl,
British also ˌläŋ-gə-
1
: placed or running lengthwise
The insect's back is black with yellow longitudinal stripes.
2
: of or relating to length or the lengthwise dimension
the longitudinal extent of the building
3
: involving the repeated observation or examination of a set of subjects over time with respect to one or more study variables
a longitudinal study of juvenile offenders over a period of five years
longitudinally
adverb
Examples of longitudinal in a Sentence
The insect's body is black with yellow longitudinal stripes.
calculating the longitudinal position of a ship
a longitudinal study of career aspirations among girls from 5 to 17
Recent Examples on the Web
Researchers conducted a large-scale, longitudinal study to understand how people across the U.S., even those far from New York City, psychologically adjusted to a national trauma over time.
—
Mark Travers, Forbes.com, 19 June 2025
The study, published in JAMA on Wednesday, looked at data on more than 4,000 kids from an ongoing longitudinal study following them for years, starting at ages 9 to 10.
—Rhitu Chatterjee, NPR, 18 June 2025
Electronic screen use and children's socioemotional problems: A systematic review and meta-analysis of longitudinal studies.
—Lydia Patrick, MSNBC Newsweek, 9 June 2025
In addition to longitudinal data spanning decades, the Framingham Heart Study provides access to midlife biological measures, like serum cortisol, as well as rich neuroimaging data, including PET scans for proteins associated with Alzheimer’s disease, like amyloid and tau, Salardini says.
—Elizabeth Yuko, Flow Space, 5 June 2025
See All Example Sentences for longitudinal
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Mark Travers, Forbes.com, 19 June 2025
The study, published in JAMA on Wednesday, looked at data on more than 4,000 kids from an ongoing longitudinal study following them for years, starting at ages 9 to 10.
—Rhitu Chatterjee, NPR, 18 June 2025
Electronic screen use and children's socioemotional problems: A systematic review and meta-analysis of longitudinal studies.
—Lydia Patrick, MSNBC Newsweek, 9 June 2025
In addition to longitudinal data spanning decades, the Framingham Heart Study provides access to midlife biological measures, like serum cortisol, as well as rich neuroimaging data, including PET scans for proteins associated with Alzheimer’s disease, like amyloid and tau, Salardini says.
—Elizabeth Yuko, Flow Space, 5 June 2025
See All Example Sentences for longitudinal
Cite this Entry
“Longitudinal.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/longitudinal. Accessed 4 Jul. 2025.
Copy CitationKids Definition
longitudinal
adjective
lon·gi·tu·di·nal
ˌlän-jə-ˈt(y)üd-nəl
-ᵊn-əl
1
: of or relating to length
2
: placed or running lengthwise
longitudinally
adverb
-ē
Medical Definition
longitudinal
adjective
lon·gi·tu·di·nal
ˌlän-jə-ˈt(y)üd-ᵊn-əl, -nəl, British also ˌläŋ-gə-ˈtyüd-
1
: of, relating to, or occurring in the lengthwise dimension
a longitudinal bone fracture
2
: extending along or relating to the anteroposterior axis of a body or part
a trypanosome which reproduces by longitudinal fission
3
: involving the repeated observation or examination of a set of subjects over time with respect to one or more study variables (as general health, the state of a disease, or mortality)
a longitudinal study of heart transplant recipients over a five-year period
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