isochore

1. (physics) A line drawn on a graph showing the variation of the pressure of a constant volume of gas as it varies with temperature.Examples: "An isochore is a curve on a PVT diagram, the pressure and temperature being variable, the volume invariable."; "Thus, an isochore transformation in this case is a transformation at constant volume."; "1.3 shows the specific heat of argon measured along the critical isochore."

2. (geology) A contour showing points of equal vertical thickness of strata; equal to an isopach if strata are horizontal.Examples: "The isochore plan of the overburden thus obtained is then placed over the isochore plan of the seam."; "Isochore maps of the sandstone bodies also indicate the presence of a number of channels flowing from the basin margin towards a central depression."

3. (genetics) A sequence of DNA that has a reasonably constant proportion of pairs of guanine and cytosine bases, and is rich in genes.Examples: "A model that accounts for the differential recognition of transgenes integrated at different chromosomal locations, is the isochore hypothesis."