Poppy seed is an Oilseed obtained from the opium poppy (Papaver somniferum). The tiny kidney-shaped seeds have been harvested from dried seed pods by various civilizations for thousands of years. The seeds are used, whole or ground, as an ingredient in many foods all over the world. As with all seeds, toasting them will bring out more of the aromatic flavor.
If your recipe calls for cracked or crushed poppy buy whole poppy seeds and crack or crush it yourself (either spin it quickly in a blender or hammer slightly in a sealable bag). This will produce the best and freshest taste.