A word, symbol, or number used as a descriptor for retrieval of information from a collection, especially in a coordinateindexing system.
用作描述符的一种字、符号或数，用于从某一集合中，特别是从某一配位标引系统中检索信息。
2
This type of coordinateindexing is said to be manually operated, since the recording of the accession number onto the features card is done by hand.
这种类型组配被称为是人工操作的，因为在特征卡上写登记号是用手写的。
3
A document should be indexed more generally first by descriptors, such as coordinateindexing, hypernym indexing and proximate indexing; then by free term specially, namely double indexings.