[ebb_earl_co]

What is a fifth column? For that matter, what are the preceding four columns?

[fifilura]

A fifth column is a group of embedded traitors.

I am not sure the word is suitably used here.

Franco (loosely). "We'll be marching towards Madrid in four columns. The fifth column is already in the city".

[ebb_earl_co]

As in Francisco Franco? Thank you for the definition and some bonus etymology!

[vincnetas]

https://en.m.wikipedia.org/wiki/Fifth_column

A fifth column is a group of people who undermine a larger group or nation from within, usually in favor of an enemy group or another nation.