1 xz is a command line tool with syntax similar to that of gzip. 2  xzdec is a decompression-only tool smaller than the full-featured xz tool. 3  A set of shell scripts (xzgrep, xzdiff, etc.) have been adapted from gzip to ease viewing, grepping, and comparing compressed files.
Epoch (astronomy), a moment in time used as a reference for the orbital elements of a celestial body. Epoch (cosmology) or cosmologic epoch, a phase in the development of the universe since the Big Bang. Epoch (geology) or geologic epoch, a span of time smaller than a period and larger than an age.
Definition of 'epoch'. epoch (iËpÉk , US epÉk ) If you refer to a long period of time as an epoch, you mean that important events or great changes took place during it. The birth of Christ was the beginning of a major epoch of world history. Synonyms: era, time, age, period More Synonyms of epoch. 2. countable noun.