The CAS Lexicon tab enables you to search the CAS Lexicon and add terms. The major components are a Concept/General Subject vocabulary; a taxonomic vocabulary for biological genus and species terms; and Compound classes, including the chemical substances most frequently indexed by CAS, common synonyms, and related terms.

There are two ways to add CAS Lexicon terms through the CAS Lexicon tab to your search queries:

Search for Lexicon Terms

If you are not already in the CA/CAplus files:

Click the Databases tab.
Select the CA and CAplus files, and then click the Enter button.
At the Command Line, enter the SEARCH command.
On the CAS Lexicon tab, begin to enter your search term; suggested terms will dynamically appear as you enter text. Selecting one of these terms automatically performs the search. Otherwise, enter your term and click the magnifying glass icon.
Matching lexicon terms display along with synonyms, related terms, and narrower terms (expanded by default). Click the arrow next to the other categories to expand/collapse the list. The shaded dots to the right of each term indicate the number of indexed documents for the term relative to the other terms in the list; in the example below, there are more indexed documents for "Peptides" compared to "Polyamide fibers."

Select the terms to include in your query or click the Add All link to add relationship codes in the CT field.
Select the Boolean operator.
Click the Add Term button.

The terms are added to your SEARCH statement.

Use Lexicon Matches

If you are not already in the CA/CAplus files:

Click the Databases tab.
Select the CA and CAplus files, and then click the Enter button.
At the Command Line, enter a SEARCH or EXPAND command, and then enter a term. Lexicon matches to your terms appear in the yellow box; clicking a match highlights it on the CAS Lexicon tab.
The Narrower Terms category is expanded by default. Click the arrow next to the other categories to expand/collapse the list. The shaded dots to the right of each term indicate the number of indexed documents for the term relative to the other terms in the list; in the example below, there are more indexed documents for "Peptides" compared to "Polyamide fibers." Select a synonym, related term, or narrower term or click the Add All link to add relationship codes in the CT field.
If necessary, select the Boolean operator.
Click the Add Term button.