  We investigate monoidal categories of formal contexts, in which states
correspond to formal concepts. In particular we examine the category of bonds
or Chu correspondences between contexts, which is known to be equivalent to the
*-autonomous category of complete sup-lattices. We show that a second monoidal
structure exists on both categories, corresponding to the direct product of
formal contexts defined by Ganter and Wille, and discuss the use of these
categories as compositional models of meaning.
