Mostly seen in compounds:
等温过程 (isothermal process, thermodynamics),
等温线 (isotherm, meteorology / cartography),
等温吸附 (isothermal adsorption, chemistry). The
等- prefix forms a productive 'iso-' family:
等压 (isobaric),
等容 (isochoric),
等高 (contour-line, equal-elevation).
