DeMundo 149:1 :ܟܕ ܡܬܥܨܪ ܐܐܪ ܘܡܬܦܘܫܫ ܫܘܠܗܒܐ ܕܒܗ‏ : when the air is compressed and the burning in it is dissipated
See the entire entry for pwšš vb. to separate, make dissipate