‘Greenpoint’ is arguably now a term for rock climbers. According to climbing blog Planet Mountain the term means ‘climbing a sport route with the holds but using trad[itional] gear such as nuts and camming devices.’
Famous climber Kurt Albert developed the practice of painting a red X on spots in his climbs that he did not need to step or grab onto, finally painting a final X when he completed his ascent. This introduced the term ‘redpoint’ to the climbing world – of which I personally haven’t climbed anything but stairs and walls in years.
Several message boards featured the usual eye-rolling at naming anything. One post pointed out that ‘It’s actually called real rock climbing.’
Greenpoint’s name was, as the story goes, coined by Dutch sailors in the days of New Amsterdam. Sailors traversing their way up the East River would spy the jut of vegetated marshy land where Freeman and Green streets now end and exclaim ‘Green Pernt!’ before having a refreshing dip in Newtown Creek.
Of course, the area also used to be called Cherry Point and who knows why?
The OED contains no entry for ‘greenpoint.’ Nor does any other dictionary searched – aside from the Urban one, which cites the Brooklyn neighborhood.