Definition of "dex"

The data points for low-<nH> paths are scattered more widely than those for denser sight lines, because O/H ratios for such paths shorter than 800 pc are generally about 0.10 dex lower than the values for longer ones.

2004, Cartledge et al 2004, The Homogeneity of Interstellar Oxygen in the Galactic Disk, Abstract, The Astrophysical Journal, Volume 613, Issue 2, pp. 1037-1048

Establish a proccing percentage of a weapon by putting it in the primary hand and then put it in your offhand and check the proccing percentage with varying levels of dual wield skill (while keeping level and dex constant).

2000, Billy Shields, “The truth about offhand procs”, in alt.games.everquest (Usenet)

Two blocks west of the Chat, in a teashop called the Jarre de Thé, Case washed down the night's first pill with a double espresso. It was a flat pink octagon, a potent species of Brazilian dex he bought from one of Zone's girls.

1984, William Gibson, Neuromancer (Sprawl; book 1), New York, N.Y.: Ace Books, page 7