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

John Gottman’s own longitudinal study found that couples with children often experience a staggering 67% drop in marital satisfaction after having children. —Mark Travers, Forbes, 5 Nov. 2024

This lack of longitudinal data gives health practitioners pause about teens’ future health. —Lauren J. Young, Scientific American, 25 Oct. 2024

Related article Weekend-only workouts may also be protecting your heart health The scientists examined two sets of survey data from the Mexico City Prospective Study, a longitudinal study that followed the health of thousands of people in the Mexican capital over many years. —Lianne Kolirin, CNN, 30 Oct. 2024

Finally, this study does not take into account other confounding influences such as socioeconomic status and peer effects—an indication that the research on teen marijuana use should be done by using longitudinal studies to understand their trends. —Dario Sabaghi, Forbes, 29 Oct. 2024

Word History

First Known Use

15th century, in the meaning defined at sense 2

Phrases Containing longitudinal

• longitudinal wave

Kids 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

-ē

adverb

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

longitudinally

-ē 

adverb