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

The nonprofit’s longitudinal study has surveyed nearly 1,700 young LGBTQ+ people every six months since September 2023. — Theresa Gaffney, STAT, 21 Oct. 2026

Restraints called longitudinal anchors run lengthways along the home to prevent tipping on that axis. — Daniel Wolfe, Miami Herald, 21 Oct. 2026

The longitudinal strips of the rose petals did indeed curl up, suggesting that the petal preferentially curves in this direction. — Manon Bischoff, Scientific American, 13 Oct. 2026

Indiana has served as CARE’s administrative operations core, while Michigan has led the group’s longitudinal clinical study, which involves dozens of other universities. — Daniel Libit, Sportico.com, 12 Oct. 2026

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