1. very sheer and light; almost completely transparent or translucent.
2. delicately hazy.
Example: "...the very mist on the Essex marshes was like a gauzy and radiant fabric, hung from the wooded rises inland, and draping the low shores in diaphanous folds." (Joseph Conrad, Heart of Darkness)
Origin: 1605–15; < ML diaphanus < Gk diaphan(s) transparent (equiv. to diaphan-, s. of diaphaínein to show through.