I was thinking about my post regarding "immaculate degeneration," and I began to wonder about the relationship of "macular" to "immaculate." The OED cites "maculate" as a verb, noun and adjective. The noun means a blemish or imperfection; the adjective means spotted, stained or soiled, and the OED says this is the "implied antithesis" to immaculate; then the verb means to soil to stain. In the retina of they eye is the macula lutea, which does derive from the same Latin word that immaculate or maculate derive from; that's the Latin word macula that means "spot." The Latin word lutea means "yellow." the macula lutea is a yellow spot near the center of the retina. My friend wasn't all that far off with her "immaculate degeneration."
Another word from Latin maculo (maculare, maculavi, maculatus) 'to spot, stain;defile' is Italian macchiato 'spotted' (the espresso drink has a little steamed milk in it and the surface should be spotted).
I ran across this recently when looking for the origins of the French word for "scale model," which is is "maquette." Spanish and Czech are similar, but it appears that Italian doesn't use it in this way.
I've been thinking about maculate and immaculate ever since this post. I wonder if the thought by some as "sex being dirty" came from the immaculate conception? That is, it was a conception that wasn't blemished or spotted (i.e., dirty).