Rural or remote areas far from cities, usually considered isolated or underdeveloped; the countryside.
From Tagalog 'bundok' meaning mountain, brought into English by American soldiers during the Philippine-American War (1899-1902). The word contracted and evolved into 'boonies' as a slang term for remote areas. It entered American military vocabulary and eventually mainstream English.
American soldiers invented this slang while fighting in the Philippines over a century ago, and it stuck around so well that most English speakers don't realize they're using a Tagalog word when they say 'boonies'!
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