The word, "about".
When do I use, "acerca de" or "sobre".?
Example: Christmas is about... - La Navidad es acerca de/sobre...
Edit: Christmas is about Jesus Christ. (And/Or) Christmas is about being with friends or family.
Thanks.
3 Answers
In Spanish "acerca de" will be translated as concerning or about something "La pelicula es acerca de la segunda guerra mundial" "The movie is about the second world war" And "sobre" will be translated the same way but it is more usual to write "trata sobre" "La pelicula trata sobre la segunda guerra mundial" Posible translation will be... "The movie is about the second world war" same meaning You can use both.
Here is another one a little more complex:
La trama de la pelicula gira en torno a la segunda guerra mundial...
You can also use "se trata de" La navidad se trata del nacimiento de Jesucristo. The meaning is more like "it deals with" (o algo parecido).

See Ikigreg's answer and disregard mine.
The nuance of "acerca de" is "around" and that of "sobre is" "covering". Your sentence begins "Christmas is about..." You are thinking in the wrong direction here in my opinion. The sense of your sentence is "Christmas concerns..." or "We celebrate Christmas because..." Maybe you can edit your post to reflect this idea because I don't need "about" in this sentence as far as I can tell.