(n) A regional or social variety of a language distinguished by pronunciation, grammar, or vocabulary, especially a variety of speech differing from the standard literary language or speech pattern of the culture in which it exists: Cockney is a dialect of English.
There was a 4 mm nodular opacity in the right lower lung. A ct scan of 10/06 showed linear scarring in both lungs but no mention of nodules. A chest xray in 4/2007 showed a round density in the right perihilar region.
Opacity is an intrinsic property of material, it can not depend on its thickness. After all, even glass will not let light shine through it if it is a kilometer in thickness. Truly opaque materials do not let the light shine through them no matter what is the thickness.