I have a few friends that always ask why we would have a section of Brooklyn with such a weird name. So here's your answer.
"Flatbush", one of the six original towns settled on Long Island, was orignally known as "Vlackte Bosch" -- Dutch for (roughly) "flat, wooded area" or "a plain with woods". After the British took over New Amsterdam in 1664 the name was anglicized to "Flatbush" (sort of the same way "Breuckelen" became "Brooklyn") Flatbush was actually first known as "Midwout", and was settled sometime around 1645-1651.
Kind of like how Buffalo was a bastardization of Bon Fleur (beautiful flower) as the city was called by the French prior to its English "translation."