In French there are various words for what in English we would call a stock - that is, a savoury liquid made by simmering meat, bones, vegetables and aromatics in water for several hours, used as the base for soups and sauces.
In French cuisine you may choose to make a bouillon. This is a fairly typical every day stock, cooked for 2-3 hours and using cheap offcuts of meat, but not many marrow bones. You can use it for soups, stews, sauces and risottos.
If you clarify a bouillon by adding egg white, which coagulates and lifts out the impurities, it becomes a consommé, to be used for clear, refined soups and aspic. A court-bouillon is a weak bouillon created by shortening the simmering time to an hour or less and diluting the stock produced even further with white wine. It is generally only used for fish or very delicately flavoured poached dishes. If you reduce a bouillon or court-bouillon it becomes a strong flavoured stock known as a fumet.
Most delicious of all, if you make a full bodied stock, in a pan packed with bones and vegetables and cooked for 4-6 hours on the gentlest heat, you have made a fond. The word fond means 'base'. They can be blanc, made from veal or poultry, or brun, made with roasted bones, for extra colour and flavour. A fond should gel when it cools because the longer cooking converts the collagen in the meat to gelatin. Fonds are used to make many rich and unctuous sauces such as veloutés and demi-glaces.
Recently I discovered that an excellent way to make a fond was to put a stock pot on the stove at lunch time, then go to Chateauroux for the afternoon, forgetting to turn off the heat.
home to a charred and ruined stockpot.