What is "Biscuits and gravy"?

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What exactly is the American food Biscuits and Gravy? I've looked on the internet and found a range of different recipes. Is it just a generic term for some meat in a sauce made of flour, meat stock and milk on some sweet biscuits? Or is there a specific recipe? I once read a recipe which had minced meat, condensed milk, flour on "graham crackers" which are called - I believe - digestive biscuits here in the UK. But, subsequently heard of other recipes. Can you help me?