"The thesaurus of occupational therapy subject headings is a reference guide for use with OT SEARCH, an online bibliographic database which indexes the holdings of the Wilma L. West Library. This compilation consists of a controlled vocabulary based on the National Library of Medicine’s Medical Subject Headings (MeSH). OT Search users will find this tool useful in performing compact and efficient search strategies. In comparison to a broad keyword search, a search strategy utilizing valid subject headings will generate the most pertinent references related to a particular topic. It is, therefore, advisable to select appropriate terms from the thesaurus before performing your search in OT SEARCH. This thesaurus comprises two major sections: I. Alphabetical Subject Listing: A listing of all the subject terms in alphabetical order. Each entry consists of a hierarchical tree number, a note and annotation when appropriate, and a definition of the term proper. While approved subject headings are printed in capital letters (e.g. SENSORY INTEGRATIVE DYSFUNCTION), related terms are printed in lower case (e.g. Early intervention programs), with a reference to the approved subject headings (e.g. Tactile Defensiveness, use SENSORY INTEGRATIVE DYSFUNCTION). In some cases, the searcher is directed to related terms by a 'see also' reference (e.g. NURSING HOMES, see also HOMES FOR THE AGED). Some subject headings are inverted for focus purposes (e.g. health insurance is listed in the thesaurus as INSURANCE, HEALTH). II. Hierarchical Classification Scheme: A listing of tree numbers in hierarchical order. Each term is assigned a unique alphanumeric number which places it in an hierarchical classification scheme or 'tree' with a broader, narrower, or related term. The hierarchical classification scheme consists of a number of tables which classify the subject headings into several categorical layers. The major categories cover broader concepts such as anatomy, diseases, chemicals and drugs, procedures and techniques, equipment and supplies, behavior and behavior mechanisms, biological sciences, physical sciences, social sciences, technology, humanities, information sciences, persons, health care and geographic names. These categories are further broken into a strata of categories. Each table consists of an array of tree numbers and matching subject headings which are indented according to their hierarchical structure. A hyphen [-] is used to represent the status of the terms in the hierarchical scheme. The more indented the term is, the narrower in scope."