"I wait until six."
Translation:Aspetto fino alle sei.
What function does 'alle' serve here?
"I wait until ??? 6"
The mouseover says "a", which is unhelpful.
Think of time as a number of hours: partiamo alle sei, arriviamo alle otto, mangiamo alle dieci...
The phrase "fino alle" (fino+a+le) is used as a unit, not individual words. In this case it literally means "until at the six (hour)", time being thought of differently in Italian.
No, fino a is a preposition (A preposition links nouns, pronouns and phrases to other words in a sentence) and finché is a conjunction (a word that connects (conjoins) parts of a sentence or two sentences). (finché = fino a che)
Aspetto fino alle sette.
Aspetto finché l'orologio non batte le sette.