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.
decade. 1  a group of ten. 2  a period of ten years; esp., in the Gregorian calendar. 3  officially a ten-year period beginning with the year 1, as 1921-1930, 1931-1940, etc. 4  in common usage, a ten-year period beginning with a year 0, as 1920-1929, 1930-1939, etc.