"computer operating system using a disk storage device," 1967, acronym of disk operating system.
also metre, "fundamental unit of length of the metric system," originally intended to be one ten-millionth of the length of a quadrant of the meridian, 1797, from French mètre (18c.), from Greek metron "measure," from PIE root *me- (2) "to measure." Developed by French Academy of Sciences for system of weights and measures based on a decimal system originated 1670 by French clergyman Gabriel Mouton.
"of or pertaining to the science or study of wealth or riches," 1853, from Greek ploutos "wealth" (see Pluto) + ending from economic. Fell from currency 1870s, revived 1990s. Related: Plutonomy (1851); plutonomics (1991, a 19c. word for "the science of wealth and the natural laws governing its production and distribution" was plutology); plutonomist (1869).