faire signe vs faire un signe

[vizz2]

In Larousse dictionary there's an example:
il lui a fait signe depuis sa fenêtre - he waved to him from his window
I think it should be "il lui a fait un signe depuis sa fenêtre"
I'm just curious is it a mistake or some rule I don't know yet, because such a serious dictionary shouldn't use colloquial language (I assume that in colloqiual language one omits articles).

 

[Micia93]

"faire signe" is a set expression, but both are correct
"faire un signe" is maybe more specific, you can add "faire un signe de reconnaissance" for instance, whereas, no adding to "faire signe"

:=)

 

[Quaeitur]

As Micia said, faire signe is a set expression that means to make a gesture that acknowledge someone's presence (to wave or nod at someone for example) or, figuratively speaking, to send a message to someone. This is standard, not colloquial, language. No article is needed here.

Faire un signe à quelqu'un is much more prosaic and means only to make a physical gesture (a wave or nod) when meeting someone. It doesn't have a figurative meaning.