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
This longitudinal cohort study recruited 310 adult patients with a 12-month history of asthma symptoms and followed them for a period of six months.
—
New Atlas, 11 July 2025
The doctor’s observation triggered a longitudinal study of potential causes.
—Kevin Kruse, Forbes.com, 11 July 2025
Opposite Mary is John the Baptist, and those below him form the other longitudinal dividing line.
—Mary Jo Bang
july 9, Literary Hub, 9 July 2025
The consequences of misdiagnosis University of California, Berkeley’s Hinshaw has spent more than two decades running the largest longitudinal study of ADHD in girls in existence, known as the BGALS study.
—Daliah Singer, Smithsonian Magazine, 9 July 2025
See All Example Sentences for longitudinal
Examples are automatically compiled from online sources to
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New Atlas, 11 July 2025
The doctor’s observation triggered a longitudinal study of potential causes.
—Kevin Kruse, Forbes.com, 11 July 2025
Opposite Mary is John the Baptist, and those below him form the other longitudinal dividing line.
—Mary Jo Bang
july 9, Literary Hub, 9 July 2025
The consequences of misdiagnosis University of California, Berkeley’s Hinshaw has spent more than two decades running the largest longitudinal study of ADHD in girls in existence, known as the BGALS study.
—Daliah Singer, Smithsonian Magazine, 9 July 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 21 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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