|Plural for things that can be counted||"TUBES"|
|Singular for "mass" nouns||"WOOD"|
|Singular for processes, properties, and conditions||"REFRIGERATION"
|Not inverted||"RADAR ANTENNAS"
(rather than "ANTENNAS, RADAR")
|Excluding prepositions||"CARBOHYDRATE METABOLISM"
(rather than "METABOLISM OF CARBOHYDRATES")
|Excluding punctuation marks, diacritics, special characters, and abbreviations||"COOPERATIVE PROGRAMS"
(rather than "CO-OPERATIVE PROGRAMS" or "COÖPERATIVE PROGRAMS")
(rather than "(MUSICAL) NOTES" or "MUS. NOTES"
A unique term may be created out of a homograph by adding a parenthetical qualifier; for example, "PORT (WINE)".
You may note that including parentheses is contrary to the guideline given above; namely, to avoid punctuation. A unique term may also be created out of a homograph by adding another word without punctuation; for example, "PORT WINE".
For example, "TRAFFIC STATIONS", because it can be used to replace a search for "AIRPORTS OR BUS TERMINALS OR TRAIN STATIONS OR HELIPORTS OR...".
For example, "EMPLOYMENT OF SPECIFIC GROUPS" to clarify the relationship between "EMPLOYMENT" and "YOUTH EMPLOYMENT".
|For example, this picture shows things that are not referred to in the caption, including a bottle. After examining the picture, you might decide to add "BOTTLES" to your list of terms.|