(chemistry)
A crystalline lattice or receptor molecule for the strong and selective binding of a cationic, anionic, or neutral organic, inorganic, or biological substance (guest) by means of electrostatic, hydrogen-bonding, van der Waals, or donor-acceptor interactions. Examples include clathrates, crown ethers, cryptands, cyclodextrins, calixarenes, cavitands, cyclophanes, and cryptophanes. Also known as host structure, host substance.