An official website of the United States government.

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Tips for the Thesaurus

"Select display contents"

Terms are displayed in alphabetical order. Cross references (Use terms) for NAL Agricultural Thesaurus terms appear in italics. Click on terms to show their complete records. The gray "New Search" button returns you to the "Search and Browse" page.

For additional information on the structure of the NAL Agricultural Thesaurus, consult the Thesaurus Structure page.

Term list (default)

With this selection, the results page displays an alphabetical list of terms that fit the search criteria.

This is the results display for a search for Terms which contain this character string... "artificial":

Term + relationships

The results page shows an alphabetical list of terms that fit the search criteria along with any of their:

  • Spanish translation
  • Broader Terms/Narrower Terms
  • Use terms (cross references)
  • Related Terms
  • Definitions/Scope Notes

This is the "Term + relationships" display for "artificial sweeteners":

This is also the display format that appears, by default, after clicking on a term.

Term + 2-way hierarchy

This option provides an alphabetical list of terms that fit the search criteria along with their:

  • Broader Terms (indicated by ":")
  • Narrower Terms (indicated by ".")

This is the Term + 2-way hierarchy display for a search for for "artificial sweeteners":

The "Term + 2-way hierarchy" display option is also available from by clicking the gray "Show Hierarchy" button near the top of the window.

"Select a search method"

Terms which START with...

This option produces a list of NAL Agricultural Thesaurus term(s) that begin with the requested character string or word(s).

This is the term list display of "Terms which START with..." the character string "intens":

Note: An alphabetical list of thesaurus terms that follow the last qualifying term of the search is also provided in the results.

Terms which CONTAIN...(default)

This selection returns a list of terms that include the requested character string or word(s) as it appears anywhere in NAL Agricultural Thesaurus terms.

These are the "Terms which CONTAIN..." the character string "intens" displayed as a term list:

"Thesaurus term (Subject) search in articles (AGRICOLA)"

Subject terms or NAL Subject Headings are preferred terms from the NAL Thesaurus that help in the retrieval of data containing synonyms or other variants of them.

How it works:

  1. Find a term in the NAL Thesaurus that you are interested in: For example, "corn ears".
  2. Go to "Advanced tab" at NAL Article Citation Database and type "corn ears" in the search box, select "as a phrase" from the first dropdown and "Subject" from the second dropdown and hit the search button.
  3. You will retrieve all the articles containing the phrase "corn ears" (NALT preferred term), maize ears (synonym) and many hidden variants of the corn ears (such as ear kernel, ear of corn, tassel and ear, maize ear, etc.) in one search.

Common Questions

Q. Can I use the thesaurus to search the AGRICOLA bibliographic database?
A. Yes. You can search AGRICOLA and Google Scholar directly from the results pages where the "Use your term for SEARCH in:" button appears. Select the desired database from the dropdown list to the right of the button.

However, more search options can be found at the AGRICOLA search page, the preferred method.

Q. What is a character string?
A. A character string is a group of letters and/or numbers which form all or part of a word.

Q. How is a truncation handled by the search?
A. The search is character string based. Using the default search method, Terms which CONTAIN..., the search automatically looks for the character string with left- and right-truncation assumed.

A search for the character string "intens" will return this term list:

Similarly, left- and right-truncation is the default search method for words or phrases. A search on "harvest" finds:

  • combine harvesters
  • harvest date
  • harvesting
  • postharvest diseases

Q. Is the search case-sensitive?
A. No. A search for "Western" or "western" will return the same results.

Q. The results have italicized terms. What do the terms in italics mean?
A. A character string is a group of letters and/or numbers which form all or part of a word. These are synonyms, or cross references, and lead you to the preferred term in the Thesaurus. (See Use terms)

Q. Should I include hyphens and commas in my search?
A. The Thesaurus search is punctuation sensitive. A search, for example, for "1,4" will return different results than a search for "14."

Q. Why are there words in parentheses at the end of terms ?
A. Information in parentheses is used to clarify the meaning of the term. The words or phrases in parentheses are part of the complete thesaurus term.

In the NAL Agricultural Thesaurus, parentheses are most commonly used to distinguish between homographs, words that are spelled alike, but have two or more different meanings, such as:

  • parity (economics)
  • parity (reproduction)
  • dams (hydrology)
  • dams (mothers)
  • curing (crops)
  • curing (food products)
  • curing (nonfood products)
  • curing (plasmids)

Q. How do I search for acronyms, abbreviations or initialisms?
A. Search these without punctuation:


Acronyms, abbreviations or initialisms can be confusing: Does "PTO" stand for "power take offs", "Patent and Trademark Office" or "Parent-Teacher Organization"? Generally the NAL Agricultural Thesaurus includes acronyms, abbreviations or initialisms as cross references (Use terms).

Q. Can I search by enzyme classification number?
A. Yes, Enzyme Classification numbers are cross references in the thesaurus. (See Use terms.) Use this format for searching:


The periods are required.

A search "EC 3.2." to find all the enzymes in the "glycosidases":

Q. Can I search "common names" to find "Latin names"?
A. Yes. Many common names appear in the NAL Agricultural Thesaurus as cross references (See Use terms.) for Latin names:

  • kudzu Use Pueraria montana var. lobata
  • Atlantic salmon Use Salmo salar

Q. I am searching for chemicals and enzymes such as "glucan 1,4-alpha-glucosidase" and "(s)-2-hydroxy-acid oxidase". Do I need to use the hyphens, commas and parentheses to search?
A. Yes you can, but it is not the preferred method. A search on the typical convention will find terms, that is, a search on "1,4" will retrieve "1,4-alpha-glucosidase" and will not find "carbon-14 dating". If you are not sure how to exactly spell the chemical name, use character strings such as "glucosid" or "carboxylic" in order to find complex chemical names. This is the preferred method of searching chemical names.

Q. How can I see terms in Spanish?
A. You can view the Spanish translation of English terms by clicking on the translated term under Spanish in the Term + relationships or Term + 2-way hierarchy display. It is recommended that you use the Spanish search interface to view each term's complete word block.

Q. Are Boolean operators(AND, OR, NOT) supported in the search?
A. No. The search is based on character strings.

Q. Can I use phrases?
A. When searching for multi-word thesaurus terms, brief two or three-word noun/gerund phrases return the best results, such as:

  • animal nutrition
  • Consumer Price Index
  • Pueraria Montana
  • continuous cropping

Do not enter searches in the form of a question or description:

  • DO NOT SEARCH: Do you have irrigation words?
  • SEARCH: irrigation
  • DO NOT SEARCH: Show the economics words.
  • SEARCH: economics

Q. What are Broader and Narrower terms?
A. Broader terms represent more general concepts than subordinate Narrower terms. These are called "Hierarchical" thesaurus relationships. (More...)

Q. What are Related terms?
A. Related terms users to other concepts in the Thesaurus that may be of interest. These are known as "Associative" thesaurus relationships. (More...)

Q. What are Definitions and Scope Notes?
A. Definitions provide meanings for terms, while Scope notes clarify the meanings and applications of terms in relation to other terms in the NAL Agricultural Thesaurus. (More...)

Q. What are "Use" terms?
A. The "Use terms" (Use/Used for | USE And Type USE FOR And Type) are cross references. They indicate terms that represent the same or nearly the same concepts as Thesaurus terms. These are "Equivalence" thesaurus relationships. (More...)

Q. What does "Show Hierachy" mean?
A. This option provides an alphabetical list of terms that fit the search criteria along with their Broader Terms, indicated by ":" and Narrower Terms, indicated by ".".

Q. What does "Use your term for SEARCH in:" mean?
A. This feature allows you to search AGRICOLA and Google Scholar directly from the results pages. Select the desired database from the dropdown list to the right of the button.

Q. What does "New Search" mean?
A. This button returns you to the NAL Agricultural Thesaurus search page and clears your previous search criteria.

Q. I didn't find any terms. ("No records found") What can I do?
A. Try these ideas:

  1. Check your spelling.
  2. Shorten your search to a single word or phrase. 3) Do not include these characters:
    • asterisk (*)
    • questions mark (?)
    • plus (+)
    • exclamation point (!)
  3. If you included a hyphen or comma, try your search without it and vice versa.
  4. If you have chosen Terms which START with... as the search method, consider selecting Terms which CONTAIN... to broaden the possibilities.
  5. If you are confident you are receiving the "No records found" message in error, please contact the NAL Staff.

Q. I searched "consumer index". Why didn't I find "consumer price index" in the results?
A. The search is based on character strings and not Boolean operators. Multi-word terms such as "consumer price index" would have been found with "consumer" or "index" or "price index". (See also Phrases)

Q. I found too many terms. ("No records found") What can I do?
A. Try these ideas:

  1. Choose character strings very carefully. A search for "ag" will retrieve thousands of NAL Thesaurus terms for the search results.
  2. If you are searching for a sort term such as "cat" or "dog", change "Select a search method" to Terms that START with...
  3. Lengthen your search to include more specific information. Instead of beginning a search for breeds of dogs with "dogs", search "dog breeds." Or, instead of looking for terms on the chemistry of soils using "soils", search "soil chemistry."
  4. Search a discipline name, such as "economics" or "physics", to find that term. Click on the term and explore the hierarchies to find terms in that subject area.
  5. Use the Browse Topics option on the Thesaurus search page.

Q. I have a suggestion for the Thesaurus/I need more help.
A. Please contact the NAL Staff if you have a suggestion, question or concern.