In manual data processing, a card index system in which individual attributes are represented by holes in certain areas of the card. The presence or absence of a particular attribute can be checked by placing one card on top of another.

• 人工数据处理技术中的一种卡片索引方法。在该方法中,各个属性是用卡片上某个区域中的孔来表示的。可将一张卡片放在另一张上面来检查其特定属性的有无。