co~dec [576KB] noun 1. (acronym for "coder/decoder") the term in communications engineering used in reference to integrated circuits, or chips that perform data conversion. 2. (acronym for "compression/decompression") an algorithm, or specialized computer program, that reduces the number of bytes consumed by large files and programs. - composed: 11.2003. - source material: CNN News International - 25.11.2003 - 18:00-19:00 GMT. - requirements: Flash6. - recommended: sRGB display @ 1600x1200 + IE6 + hi-spec CPU.