Full Idea
The Epicurean atomists also defined body in terms of the property of being sensible, in order to distinguish it from empty space, which is not sensible.
Gist of Idea
Epicurean atomists say body is sensible, to distinguish it from space.
Source
Daniel Garber (Leibniz:Body,Substance,Monad [2009], 1)
Book Reference
Garber,Daniel: 'Leibniz: Body, Substance, Monad' [OUP 2009], p.26
A Reaction
This is a very illuminating bit of background, for those of us who have the knee-jerk reaction that monadology is barking mad.