fifty-fiftyˌfifty-ˈfifty adverb, adjective spoken 
The companies split the profits fifty-fifty. We’ll share it on a fifty-fifty basis.go fifty-fifty (on something) (=share the cost of something equally) We went fifty-fifty on a new TV set.2if there is a fifty-fifty chance of something happening, it is as equally likely to happen as not to happen SYN equal: a fifty-fifty chance of winning
Longman Language Activatorwhen two different results are possible
informal if you say that something such as a game or a decision could go either way , you mean that either of two results is equally possible: · Legal experts following the case believe the trial could go either way.· Spurs are a goal up but there are ten minutes to go and the match could still go either way.
a borderline case is a situation in which the decision is not certain, for example about whether someone should pass an exam, get a job etc: borderline case/decision etc: · In borderline cases we look at a student's class work to decide the final exam result.· It was a borderline decision whether to send him to prison or not.
spoken informal if you say there is a fifty-fifty chance of something happening, you mean there is an equal chance of it happening or not happening: · The weather forecast said there was a fifty-fifty chance of rain.be fifty-fifty (=there is a fifty-fifty chance): · It'll be a tough game -- I'd say our chances of winning are fifty-fifty.
spoken say this when you do not know which of two possibilities someone will choose, and you think each is equally likely: · "Have you decided where to go on holiday?" "Well, it'll be either Portugal or Turkey -- it's a toss-up."it's a toss-up between: · I don't know who'll get the job. I guess it's a toss-up between Carl and Steve.
COLLOCATIONS FROM THE ENTRY The companies split the profits fifty-fifty. We’ll share it on a fifty-fifty basis. a fifty-fifty chance of winning
1if you divide something fifty-fifty, you divide it equally between two people, companies etcdivide/split/share something fifty-fifty The companies split the profits fifty-fifty. We’ll share it on a fifty-fifty basis. (=share the cost of something equally) We went fifty-fifty on a new TV set.
We went fifty-fifty on a new TV set. a fifty-fifty chance of winning The companies split the profits fifty-fifty. We’ll share it on a fifty-fifty basis.go fifty-fifty (on something) (=share the cost of something equally) We went fifty-fifty on a new TV set.2if there is a fifty-fifty chance of something happening, it is as equally likely to happen as not to happen SYN equal: a fifty-fifty chance of winning