and stumbled upon 'boscage', an English word rarely used these days. It is in the dictionary, though:
boscage
A mass of trees or shrubs; a thicket.
The word comes from Old French 'boscage' and related to the word 'bush' - and also to 'bocage' - the word describing French pastureland divided into small hedged fields interspersed with groves of trees, or, figuratively, rural hinterland. That's where most Brits head when they move to France.
Huxley wrote Brave New World while splitting his time between England and France. So, perhaps, the bocage inspired him to use boscage in the book.
