Terrine is forcemeat—or meat that has been chopped or ground into very small pieces—that is then served at room temperature. One very common example of this is pate. Pate is originally a French dish (though many cultures have come up with their own versions using native ingredients). However, pate is so finely ground that it is almost like a thick paste. There are terrine dishes that are more roughly ground.
Terrine also refers to a kind of cookware, namely the dish used to make meatloaf. Usually, cooks will combine ingredients, and marinate them for several hours or even overnight. Then, the ingredients are mixed once again, to evenly distribute them. This is especially important of the terrine is roughly ground.
Only then is the mixture transferred to a terrine. The terrine is then covered and placed into a larger dish, which contains hot water. This cooking method allows heat to be evenly distributed across the meatloaf, so it is cooked without browning.
After the cooking time is over, the terrine is removed from the “water bath” and then cooled. Then, it is placed in the refrigerator, with a heavy object on top of it to “press” down against the mixture. This removes any air pockets and keeps the mixture smooth. The dish is often refrigerated for one to two days.
As the previous paragraphs show, terrine is quite a time consuming dish to make. Nevertheless, it is quite popular, and is seen as a “fancy” way of making meatloaf. Though it was once a “commoners” dish, eaten by French farmhands and laborers, it is now seen in the menus of the most upscale restaurants.