v. t. [ imp. & p. p. Compressed p. pr & vb. n. Compressing. ] [ L. compressus, p. p. of comprimere to compress: com- + premere to press. See Press. ] 1. To press or squeeze together; to force into a narrower compass; to reduce the volume of by pressure; to compact; to condense; as, to compress air or water. [ 1913 Webster ]

Events of centuries . . . compressed within the compass of a single life. D. Webster. [ 1913 Webster ]

The same strength of expression, though more compressed, runs through his historical harangues. Melmoth. [ 1913 Webster ]

2. To embrace sexually. [ Obs. ] Pope. [ 1913 Webster ]

3. (Computers) to reduce the space required for storage (of binary data) by an algorithm which converts the data to a smaller number of bits while preserving the information content. The compressed data is usually decompressed to recover the initial data format before subsequent use. [ PJC ]

Syn. -- To crowd; squeeze; condense; reduce; abridge. [ 1913 Webster ]

n. [ F. compresse. ] (Surg.) A folded piece of cloth, pledget of lint, etc., used to cover the dressing of wounds, and so placed as, by the aid of a bandage, to make due pressure on any part. [ 1913 Webster ]

a. 1. Pressed together; compacted; reduced in volume by pressure. [ 1913 Webster ]

2. (Bot.) Flattened lengthwise. [ 1913 Webster ]

Compressed-air engine, an engine operated by the elastic force of compressed air. [ 1913 Webster ]

. A cake yeast made by filtering the cells from the liquid in which they are grown, subjecting to heavy pressure, and mixing with starch or flour. [ Webster 1913 Suppl. ]

n. [ Cf. F. compressibilité. ] The quality of being compressible of being compressible; as, the compressibility of elastic fluids. [ 1913 Webster ]

a. [ Cf. F. compressible. ] Capable of being pressed together or forced into a narrower compass, as an elastic or spongy substance. [ 1913 Webster ]

n. The quality of being compressible; compressibility. [ 1913 Webster ]

n. [ L. compressio: cf. F. compression. ] 1. The act of compressing, or state of being compressed. “Compression of thought.” Johnson. [ 1913 Webster ]

2. (Computers) reduction of the space required for storage (of binary data) by an algorithm which converts the data to a smaller number of bits while preserving the information content. The act of compressing { 3 }. Compression may be lossless compression, in which all of the information in the original data is preserved, and the original data may be recovered in form identical to its original form; or lossy compression, in which some of the information in the original data is lost, and decompression results in a data form slightly different from the original. Lossy compression is used, for example, to compress audio or video recordings, and sometimes images, where the slight differences in the original data and the data recovered after lossy compression may be imperceptable to the human eye or ear. The JPEG format is produced by a lossy compression algorithm. [ PJC ]

. A projectile constructed so as to take the grooves of a rifle by means of a soft copper band firmly attached near its base or, formerly, by means of an envelope of soft metal. In small arms the modern projectile, having a soft core and harder jacket, is subjected to compression throughout the entire cylindrical part. [ Webster 1913 Suppl. ]

a. [ Cf. F. compressif. ] Compressing, or having power or tendency to compress; as, a compressive force. [ 1913 Webster ]

n. [ L. ] Anything which serves to compress; as: (a) (Anat.) A muscle that compresses certain parts. (b) (Surg.) An instrument for compressing an artery (esp., the femoral artery) or other part. (c) An apparatus for confining or flattening between glass plates an object to be examined with the microscope; -- called also compressorium. (d) (Mach.) A machine for compressing gases; especially, an air compressor. [ 1913 Webster ]

n. Compression. [ 1913 Webster ]

v. i. to undergo the process of decompression. [ PJC ]

v. t. to subject to the process of decompression. [ PJC ]

n. 1. the process of experiencing decompression; the act or process of relieving or reducing pressure.
Syn. -- decompression. [ WordNet 1.5 +PJC ]

n. 1. the process of experiencing decompression; the act or process of relieving or reducing pressure.
Syn. -- decompressing. [ WordNet 1.5 +PJC ]

2. the reduction of atmospheric pressure experienced by divers rising from deep water to the surface, thus reducing the concentration of dissolved atmospheric gases in the blood; -- especially applied to a gradual reduction of such pressure. [ PJC ]

3. the process, analogous to sense 2, undergone by divers in a decompression chamber, in which an artificially high atmospheric pressure is gradually lowered to normal pressure. [ PJC ]

4. a return to a normal, more relaxed state after a period of intense stress, psychological pressure, or urgent activity; -- of people. [ PJC ]

5. (Computers) the process of converting digitally encoded data from a more compact (compressed) form to its original, larger size. The process of compression and decompression may completely recover all of the original data (called lossless compression), or may lose some of the original data in order to achieve higher degress of compression (lossy compression). The latter is used especially with images or video data, which may be of very large size relative to text, and for which small changes may be imperceptible to the human eye. The JPEG data compression format is a lossy format. [ PJC ]

n. [ Cf. F. incompressibilité. ] The quality of being incompressible, or incapable of reduction in volume by pressure; -- formerly supposed to be a property of liquids. [ 1913 Webster ]

The incompressibility of water is not absolute. Rees. [ 1913 Webster ]

a. [ Pref. in- not + compressible: cf. F. incompressible. ] Not compressible; incapable of being reduced by force or pressure into a smaller compass or volume; resisting compression; as, many liquids and solids appear to be almost incompressible. -- In`com*press"i*ble*ness, n. [1913 Webster]

n. (Computers) The compression of binary data into a form which, when it is re-expanded, has most, but not all, of the original information. It is used primarily for compression of images and sounds, and is designed to provide a high degree of compression at the cost of a slight loss of data. It is expemplified by the JPEG compression standard. Images compressed by a lossy compression algorithm are re-expanded into an image close, but not identical to the original image; the difference between the original and the reconstructed image may be imperceptible to normal viewing by the eye. [ PJC ]

a. [ Pref. ob- + compressed. ] Compressed or flattened antero-posteriorly, or in a way opposite to the usual one. [ 1913 Webster ]

a. Not fully compressed; partially or somewhat compressed. [ 1913 Webster ]