De una
 

means desde luego in Colombia. Is it used this way in Mexico as well?

Not at all. It's the first time I see that expression. :thinking:

I wonder if it could be someone's shortened version of "de una vez por todas"?

I think so. It's something like all as one.

I'm not sure. "De una vez por todas" sounds more like a settling of scores, but this expression is an expression of agreement. I couldn't find where it comes from, but maybe something like "ser de una misma opinión". :thinking:


I found this place, where it's defined as Argentinian slang, and I guess 2.2. may be understood as "de una (sola) vez" (in Mexico we might say "de un jalón"). :)

What is especially strange is that in Colombia, the term seems to be used in Cundinamarca and not on the coast. I know some coastal Colomibians who do not understand it, but in the program I currently watch, which is filmed in Bogota, it is used frequently.