What does compression mean?
Compression is the act or process of pressing something into a smaller space, or the condition that results from such pressure. In everyday physical terms it describes squeezing — a compressed spring, a compressed gas, or soil compacted underfoot. The word has taken on major importance in modern technology, where data compression means encoding text, images, audio, and video so they occupy far less storage space or bandwidth; formats like JPEG and MP3 are household names built on this principle. Medicine uses the term for deliberate external pressure applied to the body, as with compression bandages or the chest compressions of CPR. Audio engineers speak of compression when narrowing a recording's dynamic range. Figuratively, compression can describe condensing a story or a historical era into a brief account. Neutral in tone but indispensable across science, medicine, and computing, it is among the most consequential words of the digital age.
nounThe act or process of pressing something into a smaller space, or the resulting state of being squeezed together. It also refers to the reduction of data's size in computing by encoding information more efficiently.
- Physical: the act or state of pressing or squeezing something into less space.
- Computing: encoding data so it occupies fewer bits or bytes.
- Medical/therapeutic: applying pressure to a part of the body, as with compression stockings or bandages.
- Music/audio: reducing the dynamic range of an audio signal.
- Figurative: condensing a text, idea, or time period into a briefer form.
"The compression of the spring stored enough energy to power the mechanism."
"Modern streaming services rely on aggressive compression to deliver video over ordinary broadband connections."
"She wore compression socks on the long flight to improve circulation in her legs."
Used when counting discrete instances, most familiarly in first aid for chest compressions during CPR.
"The paramedics maintained steady chest compressions until the ambulance arrived."
Every photo you share online survives only because compression algorithms throw away details your eye would never notice.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of compression
Compression derives from the Latin comprimere, meaning 'to press together,' formed from com- ('together') plus premere ('to press'). The noun passed into English via French in late Middle English, with senses relating to physical pressure well established by the early modern period. Its modern technological sense expanded naturally once computing required efficient storage of information. Cognates sharing the Latin root premere include English press, pressure, repress, suppress, and depress.
Related word forms
How compression is actually used
Compression is a formal-to-neutral term used across scientific, technical, medical, and everyday contexts. In engineering and computing it is largely neutral; in medical contexts it carries a therapeutic connotation. The plural 'compressions' is standard when counting instances, as in CPR chest compressions.
Easily confused with compression
Not applicable — no common confusion.