proventriculus

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The division of the stomach in birds that secretes digestive enzymes and passes food from the crop to the gizzard.
• noun A similar digestive chamber in certain insects and worms.

from The Century Dictionary.

• noun In ornithology, the glandular stomach; a second dilatation of the esophagus, succeeding the crop or craw, and succeeded by the gizzard, gigerium, or muscular stomach.
• noun In insects, the first stomach, the ingluvies or crop, being merely an expansion of the esophagus.
• noun In worms, a muscular crop.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The part of the avian stomach, between the crop and the gizzard, that secretes digestive enzymes
• noun A similar part of the digestive system of invertebrates