A headed group of material; the basic structural unit of a book component such as a chapter


A very short book component (e.g., a chapter) may contain nothing but paragraphs (and other paragraph-level elements such as figures and tables), but most book components are divided into sections, each with a title that describes the content of the section, such as “Introduction”.

Conversion Note: Sections are recursive, that is, various levels of sections are indicated by containment, not by different names for the subsections. A Section <sec> element may contain lower level sections that are also tagged using the Section <sec> element, not tagged explicitly as <sec2>, <sec3>, or <subsec1>, etc.

Conversion Note: The <sec> element can be used within <back> to tag material that has not been explicitly named as one of the other back matter components, that is, it is not named as an appendix, an acknowledgment, a glossary, etc. For example, tables are frequently placed in the back matter, with no other designation than a label such as “Table 6”, or a title such as “Epochs of Geologic Time”.


disp-level Display Level of a Heading
id Identifier
indexed Indexed
sec-type Type of Section
xml:lang Language

Model Information

Content Model

<!ELEMENT  sec          %sec-model;                                  >


The following, in order:

This element may be contained in:

<abstract> Abstract; <ack> Acknowledgments; <app> Appendix; <back> Back Matter; <body> Body of the Book; <book-front> Book Front Matter; <boxed-text> Boxed Text; <notes> Notes; <sec> Section; <trans-abstract> Translated Abstract

Tagged Example

<book-part id="bid.1" book-part-type="part" book-part-number="Part 1">
<book-part id="bid.2" book-part-type="chapter" book-part-number="1">
<title>GenBank: The Nucleotide Sequence Database</title>
<p>The GenBank sequence database is an annotated collection ...</p>
<sec id="bid.3">
<p>Initially, GenBank was built and maintained at Los Alamos 
National Laboratory ...</p>