Composition and fading in French

There is a French expression au jour d'aujourd'hui which means "as of today", however, aujourd'hui itself means "the day of today", because hui is the Old French word for "today" and aujourd' is obviously the concatenated form of "au jour de".

But it does not end there: the Old French word hui evolved from "hoc die", which means "this day" in Latin.

At the end, the best explanation of au jour d'aujourd'hui is

     (this (day)))

which is fascinating.