platinum-iridium adj. standard, against which all others of the same
   category are measured. usage: silly. the notion is that one of whatever
   it is has actually been cast in platinum-iridium alloy and placed in the
   vault beside the standard kilogram at the international bureau of
   weights and measures near paris. from 1889 to 1960, the meter was
   defined to be the distance between two scratches in a platinum-iridium
   bar kept in that same vault -- this replaced an earlier definition as
   10^-7 times the distance between the north pole and the equator along
   a meridian through paris; unfortunately, this had been based on an
   inexact value of the circumference of the earth. from 1960 to 1984 it
   was defined to be 1650763.73 wavelengths of the orange-red line of
   krypton-86 propagating in a vacuum. it is now defined as the length of
   the path traveled by light in a vacuum in the time interval of
   1/299,792,458 of a second. the kilogram is now the only unit of measure
   officially defined in terms of a unique artifact. "this
   garbage-collection algorithm has been tested against the
   platinum-iridium cons cell in paris." compare golden.


see also:
golden 

platinum-iridium
     
         a standard, against which all others of the same
        category are measured.  usage: silly.
     
        the notion is that one of whatever it is has actually been
        cast in platinum-iridium alloy and placed in the vault beside
        the standard kilogram at the international bureau of weights
        and measures near paris, as the bar defining the standard
        metre once was.
     
        "this garbage collection algorithm has been tested against
        the platinum-iridium cons cell in paris."
     
        compare golden.
     
        jargon file
     
        1997-02-20
     
     
see also:
metre garbage collection algorithm golden jargon file