lead-in vocabulary
n.
The terms included in a controlled vocabulary that are not used as headings, but which point to preferred headings.
Notes
Terms in the lead-in vocabulary are synonymous or closely related to terms in the index vocabulary. Filing all entries under one heading ensures related entries are grouped together, rather than scattered among several headings. For example, ferrotype and tintype describe the same process; in a controlled vocabulary, one would be made the preferred heading under which entries are filed, and a cross-reference would be made from the lead-in heading to the preferred heading.
