A terrine most commonly refers to a French forcemeat loaf similar to a pâté, made with more coarsely chopped ingredients. Terrines are usually served cold or at room temperature. Most terrines contain a large amount of fat as well as pork, although it is often not the main ingredient: Many terrines are made with typical French game meat, like deer and boar (which are generally not eaten any other way in France).
Not just meat. It could be a vegetarian terrine too.