isochore

This term is a specialized technical descriptor used almost exclusively within thermodynamics and chemical engineering. It describes a specific path on a phase diagram where volume is held constant, distinguishing it from an isotherm (constant temperature) or an isobar (constant pressure).

In professional scientific discourse, the term is used to analyze the relationship between pressure and temperature during a process where the container size is fixed. It is a formal, precise term and has no colloquial or metaphorical application in general English.