b'The Grammar of Subject HeadingsWhile many subject headings are simple terms like Reptiles or Electricity, other subjects can bevery complex, in some cases involving several levels of subdivision. In order to construct subjectheadings consistently the cataloger should understand the grammar of subject headings.THE FORMS OF HEADINGSSingle NounsA single noun is the ideal type of subject heading when the language supplies it. Such terms are notonly the simplest in form but often the easiest to comprehend. A choice must be made between thesingular and plural forms of a noun. The plural is the more common, but in practice both are used.Abstract ideas and the names of disciplines of study are usually stated in the singular, such asBiology or Existentialism. An action, such as Editing or Fraud, is also expressed in the singular.Headings for concrete things are most commonly in the plural form, when those things can becounted, such as Playgrounds or Children. Concrete things that cannot be counted, such as Steel orMilk, obviously remain in the singular. In most cases common sense can be relied upon. In someinstances both the singular and the plural of a word can be subject headings when they have twodifferent meanings, such as Theater for the activity and Theaters for the buildings. In the case ofArts and Art, the one means the arts in general, while the other means the fine and decorative artsspecifically.Compound HeadingsSubject headings that consist of two nouns joined by and are of several types. Some headings linktwo things because together they form a single concept or topic, such as Bow and arrow or Goodand evil; because they are so closely related they are rarely treated separately, such as Forests andforestry or Publishers and publishing; or because they are so closely synonymous they are seldomdistinguished, such as Cities and towns or Rugs and carpets. Other headings that link two wordswith and stand for the relationship between the two things, such as Church and state orTelevision and children. Compound headings of this type should not be made without carefulconsideration. Often there is a better way to formulate the heading. A heading like Medicine andreligion, for example, is less accurate than the form established in Sears, which is Medicine Religious aspects. (There is not likely to be material on the medical aspects of religion.) Onequestion that arises in forming compound headings is word order. The only rule is that commonusage takes precedence (no one says Arrow and bow), and, where there is no established commonusage, alphabetic order is preferred. Whatever the order, a See reference should be made from eitherthe second term or from the pair of terms reversed, as in Forestry, See Forests and forestry, orChildren and television, See Television and children.A-27'