In article <2ouq9s$i1o at oac4.hsc.uth.tmc.edu> PHEACOCK at utmmg.med.uth.tmc.edu (Philip Heacock) writes: >Hello, >The title says it all. What is the correct prefix for 10^-21? > >Thanks in advance, >Phil Heacock "Zepto" is the prefix for 10^-21 as far as I remember. Ole