i·so·ther·mal 
(ī′sə-thûrməl)
(ī′sə-thûrməl)adj.
1. Of, relating to, or indicating equal or constant temperatures.
2. Of or designating changes of pressure and volume at constant temperature.
3. Of or relating to an isotherm.
n.
An isotherm.
- directional
- directional antenna
- directionality
- directional signal
- direction finder
- directionless
- directive
- directly
- direct mail
- direct-mail
- direct mailer
- direct object
- director
- directorate
- directorial
- directorially
- director's chair
- director's cut
- directorship
- directory
- direct primary
- directrix
- direct tax
- direful
- direfully