# Longitudinal wave

In order to avoid the following confusion, the term pressure wave is preferred.

1. "Longitudinal" also refers to the longitudinal material direction in an orthotropic material but this meaning is unrelated to a wave.
2. Meyer (1) (equation 1.58, p. 18) equates a longitudinal wave with a dilatational wave. However, a dilatational wave is different than a pressure wave and this useage does not seem to be common.