I do not think there is an exact definition and many times the terms get used somewhat interchangeability. But I agree that in general "coin" is used for the representation of a blockchain based cryptocurrency such as Bitcoin, Litecoin, Ethereum, Zcash, etc., while "token" is used more often to represent something that is issued in an ICO offering such as OMG, EOS, etc. You will probably get dozens of different responses, especially when it comes down to the specific usages and semantics, but in general I think these loose definitions are accurate.