n. [ Iso- + Gr. &unr_; weight. ] (Phys. Geog.) A line connecting or marking places upon the surface of the earth where height of the barometer reduced to sea level is the same either at a given time, or for a certain period (mean height), as for a year; an isopiestic line.
a. (Phys. Geog.) Denoting equal pressure;
n. The quality or state of being equal in weight, especially in atmospheric pressure. Also, the theory, method, or application of isobaric science. [ 1913 Webster ]
a. [ Iso + barometric. ] (Phys. Geog.) Indicating equal barometric pressure. [ 1913 Webster ]