Dictionary
dia-
a prefix occurring in loanwords from Greek (
diabetes; dialect) and used, in the formation of compound words, to mean “passing through” (
diathermy), “thoroughly,” “completely” (
diagnosis), “going apart” (
dialysis), and “opposed in moment” (
diamagnetism).
Also, esp. before a vowel,di-.dia.
diameter.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.