N-UNCOUNT （尤指儿童的）注意力缺乏症（常使用缩略形式ADD） Attention deficit disorder is a condition where people, especially children, are unable to concentrate on anything for very long and so find it difficult to learn and often behave in inappropriate ways. The abbreviation ADD is often used. （尤指儿童的）注意力缺乏症（常使用缩略形式ADD）