I was wondering this same thing a while ago - what makes a "compound"? In the media's eyes, probably the same criteria for determining if a gun collection is an "arsenal" - rectal extrication.
They DO call the kennedy estate "The kennedy Compound".
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I guess I have both a compound and an arsenal! Woohoo!
Main Entry: com·pound
Pronunciation: 'käm-"paund
Function: noun
Etymology: by folk etymology from Malay kampung group of buildings, village
: a fenced or walled-in area containing a group of buildings and especially residences
Main Entry: ar·se·nal
Pronunciation: 'ärs-n&l, 'är-s&n-&l
Function: noun
Etymology: Italian arsenale, ultimately from Arabic dAr sinA'ah house of manufacture
1 a : an establishment for the manufacture or storage of arms and military equipment b : a collection of weapons