Mortar: A heavy stone or ceramic bowl. The concave interior can either be rough or smooth.
Pestle: A stone cylinder with a blunt round end used to crush and grind things in the mortar.
The mortar and pestle are primarily used nowadays for cooking purposes. They are used for crushing spices, mashing ingredients for marinaides, grinding nuts into a fine powder for things like marzipan or for making peanut butter. A slightly modified version of the mortar and pestle has been used by indigenous people of the Americas for thousands of years to grind corn for tortillas and other foods.
The mortar and pestle were originally used by apothocaries to grind roots and leaves and such to make their salves, oinments, and medicines.
Sure, a food processor is fast, but with a mortar and pestle, you can relieve stress and make dinner. There's something great about doing things slower and by hand. My food always comes out tasting better when I make it the old fashioned way. Brownies are so much more sastisfying when you know you crushed the chocolate, beat the batter, and chopped the nuts by hand, instead of mixing the contents of a box with water and eggs, putting it in the mixer, and pressing a button. Call me a purist, I don't mind. | 
