This is my first question on english.stackexchange.com/questions/ask. Could anyone tell me the meaning of "Twice Upon a Time"? It's the title of Doctor Who's Christmas special episode, the last of this ongoing season. I have been browsing the web for quite some time now and been exposed to a variety of uncertain answers.
As you say, "Twice Upon a Time" is the title of the Doctor Who 2017 Christmas Special.
It's playing with the standard expression "Once upon a time," traditionally used to introduce fairy stories and the like.
There is normally only one eponymous doctor in the show. This one features two.
Twice Upon a Time will see Peter Capaldi’s Twelfth Doctor team up with his earlier self the First Doctor (David Bradley), as the pair both try to avoid regenerating (and therefore changing their appearance and personality).
Personally, I am looking forward to watching it!
Now that I've watched the show (some time ago), I've edited my post to add Lawrence's comment.
It could also be a reference to the Doctor (single person, albeit appearing in two forms at the same time) needing to make the same decision twice, with the decision-making processes linked to each other temporally and perhaps organically (for want of a better term) as well.