What is, or is not, a biscuit?

I need information and opinion please! For reasons best understood by myself, I have decided to forego the eating of biscuits and cheese. Now, what is, or isn't cheese is very easy to categorise. But what of the biscuit? I know a digestive is definately a biscuit. I am confident about the biscuitness of Fox's ginger crunch creams. But soon, I enter the realms of confusion.Is the Jacobs Club a biscuit? I am, of course, familiar with the old adage "If you like a lot of chocolate on your biscuit join our club." But do they mean that the whole item is a biscuit, or just that if you like your biscuit centres throroughly covered with chocolate in the context of a chocolate bar you should join their club? If it is the former, what does that make a twix? Is that a biscuit? Surely not, it must be a chocolate bar? Of course, the Jacobs Club is individually wrapped in a manner seldom found in a biscuit, but the famously orangey and or minty Viscount are wrapped as single items. And they are definately biscuits. Aren't they?

What an uncertain world we live in. Don't get me started on Wagon Wheels...