different between compression vs diskdefragmentation

English

Etymology

Borrowed from Middle French compression, from Latin compressi?.

Pronunciation

• IPA^(key): /k?m.p???.?n/
• Rhymes: -???n

Noun

compression (countable and uncountable, plural compressions)

1. An increase in density; the act of compressing, or the state of being compressed; compaction.
2. (automotive) The cycle of an internal combustion engine during which the fuel and air mixture is compressed.
3. (computing) The process by which data is compressed.

   • Due to the presence of long-range correlations in language [21], [22] 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 [15]. 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 [19], [23], [24], and shows a robust performance when applied to correlated sequences [25] (see Materials and Methods).

4. (music) The electronic process by which any sound's gain is automatically controlled.
5. (astronomy) The deviation of a heavenly body from a spherical form.

Antonyms

• decompression
• rarefaction

Derived terms

• compression ratio
• compression wave
• data compression

Translations

References

• Compression in the Encyclopædia Britannica (11th edition, 1911)

French

Etymology

First known attestation 1314, borrowed from Latin compressi?.

Pronunciation

Noun

compression f (plural compressions)

1. compression (act, instance of compressing)
2. compression (cycle of an internal combustion engine)

Further reading

• “compression” in Trésor de la langue française informatisé (The Digitized Treasury of the French Language).

Middle French

Etymology

Old French, borrowed from Latin compressi?.

Noun

compression f (plural compressions)

1. compression (act, instance of compressing)
   • 1585, Giovanni Marinelli, Thresor des remedes secrets pour les maladies des femmes, page 761

     compression du ventre

     compression of the abdomen

Old French

Etymology

First known attestation 1314, borrowed from Latin compressi?.

Noun

compression f (oblique plural compressions, nominative singular compression, nominative plural compressions)

1. compression (act, instance of compressing)