Dictionary is a term of art. It's from NSDictionary, given Swift's obvious Obj-C influence. There's not always a single term of art in use.
Like Stack, Queue already has an obvious meaning, especially in British English, and it's one that creates a different mental model of the type's behavior than it actually has (remove from front, append on back). It also already has a particular meaning in CompSci (e.g. DispatchQueue). This is why deque was coined in the first place.
Given the original issue was one of pronunciation, isn't it simplest to conclude that English is a silly language not governed by laws and just not care? Let the debate be lost to memes like GIF.