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.
1.1 (as noun the Pleistocene) The Pleistocene epoch or the system of deposits laid down during it. The Pleistocene epoch lasted from 1,640,000 to about 10,000 years ago. It was marked by great fluctuations in temperature that caused the ice ages, with glacial periods followed by warmer interglacial periods.