Pronunciation: (lon"ji-tOOd'n-l, -tyOOd'-), [key]
1. of or pertaining to longitude or length: longitudinal measurement.
2. extending in the direction of the length of a thing; running lengthwise: a thin, longitudinal stripe.
3. Zool.pertaining to or extending along the long axis of the body, or the direction from front to back, or head to tail.
4. pertaining to a research design or survey in which the same subjects are observed repeatedly over a period of time.
a longitudinal framing member, as in the hull of a ship.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.