—compressional, adj./keuhm presh"euhn/, n.1. the act of compressing.2. the state of being compressed.3. the effect, result, or consequence of being compressed.4. (in internal-combustion engines) the reduction in volume and increase of pressure of the air or combustible mixture in the cylinder prior to ignition, produced by the motion of the piston toward the cylinder head after intake.5. reduction of the size of computer data by efficient storage.Also, compressure /keuhm presh"euhr/ (for defs. 1, 2).[1350-1400; ME ( < AF) < L compression- (s. of compressio), equiv. to compress(us) ptp. of comprimere to press together (see COM-, PRESS1) + -ion- -ION]
* * *▪ physicsdecrease in volume of any object or substance resulting from applied stress. Compression may be undergone by solids, liquids, and gases and by living systems. In the latter, compression is measured against the system's volume at the standard pressure to which an organism is subjected—e.g., the pressure of the atmosphere at sea level is the standard, or reference, for most land animals, but the standard for deep-sea fishes and similar specialized forms is the normal pressure of their environment.
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