longitudinal

IPA: ɫɑndʒʌtˈudʌnʌɫ

Relating to length, or to longitude.
Running in the direction of the long axis of a body.
Forward and/or backward, relative to some defined direction.
(sciences and social sciences, of a study) Sampling data over time rather than merely once.

Examples of "longitudinal" in Sentences

However, long-term longitudinal studies seem to reveal…
This kind of vibration is called a longitudinal vibration.
Long-term longitudinal studies would be needed to assess the validity of either perspective.
Following the Exxon Valdez spill in 1989, "We didn't do the long-term longitudinal follow up that now we all wish we had data on," says Donald Williamson, state health officer for Alabama.
"In any long-term longitudinal survey of budgetary costs, I think it would be imprudent and misleading not to adjust for the effects of inflation," says Stephen I. Schwartz, editor of the journal Nonproliferation Review and director of a 1998 study by the left-leaning Brookings Institution on long-range nuclear-weapons spending in the U.S.