- IPA: /kɒm.pɹɛʃ.ən/
- An increase in density; the act of compressing, or the state of being compressed; compaction.
- (automotive) The cycle of an internal combustion engine during which the fuel and air mixture is compressed.
- (computing) The process by which data is compressed.
- Due to the presence of long-range correlations in language ,  it is not possible to compute accurate measures of the entropy by estimating block probabilities directly. More efficient nonparametric methods that work even in the presence of long-range correlations are based on the property that the entropy of a sequence is a lower bound to any lossless compressed version of it . Thus, in principle, it is possible to estimate the entropy of a sequence by finding its length after being compressed by an optimal algorithm. In our analysis, we used an efficient entropy estimator derived from the Lempel-Ziv compression algorithm that converges to the entropy , , , and shows a robust performance when applied to correlated sequences  (see Materials and Methods).
- (music) The electronic process by which any sound's gain is automatically controlled.
- (astronomy) The deviation of a heavenly body from a spherical form.
- German: Kompression, Komprimierung
- Italian: compressione
- Portuguese: compressão, compactação
- Russian: сжа́тие
- Portuguese: compressão