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

Some recent studies of puberty blockers have failed to replicate the improvement in mental health that other studies have demonstrated, leading to calls for further longitudinal research. —Alex Morris, Rolling Stone, 20 Feb. 2025

The object suddenly shifted its longitudinal axis, aligned it with my aircraft and began to climb. —Jeffrey Kluger, TIME, 22 Jan. 2025

Accessing a patient’s longitudinal data may be difficult for a variety of reasons, including turnover or changes in benefits, but the use of national benchmarks can help employers establish measure baselines. —Dan Mendelson, Forbes, 17 Dec. 2024

Credit the heavy longitudinal channels on the outsole, which allowed the shoe to bend laterally with my foot during each step. —Joe Jackson, Outside Online, 13 Sep. 2024

Word History

First Known Use

15th century, in the meaning defined at sense 2

Phrases Containing longitudinal

• longitudinal wave

Rhymes for longitudinal

• altitudinal
• attitudinal
• latitudinal

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