When did neighborhood names come into being (Windsor Terr Park Slope, Kensington, etc.)?

Answer 1

The three Brooklyn neighborhoods you mentioned have entries in Wikipedia, but only Park Slope has any amount of history in its entry. It talks about the events that happened on the ground there, but not when it was named Park Slope. The other three names have very little history with them.

The Park Slope history mentions between 1850 and 1860 tracts of farmland were bought and then sold to residential developers. I would guess the names were associated at that time as before that time it is likely the land was know by its owners name. Smiths Farm, Jones Ranch, etc.

As far as the origin of the names, I'm sure Kensington and Windsor came from England. Park Slope came just from the land configuration and proximity to Prospect Park.

An interesting note: several popular actors performers and writers live or lived in Park Slope!