It's a new day for Forever Alones of the English-speaking world: the slang term "Friend Zone" has been added to Oxford Dictionaries, along with a bunch of other neologisms including tweetable ("suitable for posting on the social media site Twitter") and dumbphone ("a basic mobile phone that lacks the advanced functionality characteristic of a smart phone").
According to Oxford, friend zone is defined as:
(noun, informal) a situation in which a platonic relationship exists between two people, one of whom has an undeclared romantic or sexual interest in the other.
Hat tip goes to Betabeat!