Dictionary.net

• a chronic progressive anemia of older adults; thought to result from a lack of intrinsic factor (a substance secreted by the stomach that is responsible for the absorption of vitamin B12)

2006 - WordNet 3.0
By Princeton University

• a chronic progressive anemia of older adults; thought to result from a lack of intrinsic factor (a substance secreted by the stomach that is responsible for the absorption of vitamin B12)

2011 - English Dictionary Database
By DataStellar Co., Ltd