A Quick and Simple Dictionary

dex

1. Noun.  (physics, and) An order or factor of ten. Used both to refer to the function $dex(x)\; =\; 10^x$ and the number of (possibly fractional) orders of magnitude separating two numbers. When dealing with log to the base 10 transform of a number set the transform of 10, 100, and 1 000 000 is $log\_\{10\}(10)\; =\; 1$, $log\_\{10\}(100)\; =\; 2$, and $log\_\{10\}(1\; 000\; 000)\; =\; 6$, so the difference between 10 and 100 in base 10 is 1 dex and the difference between 1 and 1 000 000 is 6 dex. .
2. (abbreviation) .  dextromethorphan.