longitudinal

lon·gi·tu·di·nal

adjective \ˌlän-jə-ˈtüd-nəl, -ˈtyüd-, -ˈt(y)ü-d^ən-əl, British also ˌläŋ-gə-\

Definition of LONGITUDINAL

1

: placed or running lengthwise

2

: of or relating to length or the lengthwise dimension

3

: involving the repeated observation or examination of a set of subjects over time with respect to one or more study variables

— lon·gi·tu·di·nal·ly adverb

Examples of LONGITUDINAL

1. The insect's body is black with yellow longitudinal stripes.
2. calculating the longitudinal position of a ship
3. a longitudinal study of career aspirations among girls from 5 to 17

First Known Use of LONGITUDINAL

15th century

lon·gi·tu·di·nal

adjective \ˌlän-jə-ˈt(y)üd-^ən-əl, -nəl, British also ˌläŋ-gə-ˈtyüd-\   (Medical Dictionary)

Medical Definition of LONGITUDINAL

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>

—lon·gi·tu·di·nal·ly \-ē\ (audio pronunciation) adverb