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
specific-use Specific Use
xml:lang Language

Content Model

<!ELEMENT  sec          %sec-model;                                  >

Expanded Content Model

(sec-meta?, label?, title, 
(address | alternatives | array | boxed-text | chem-struct-wrap | 
fig | fig-group | graphic | map-group | media | preformat | 
supplementary-material | table-wrap | table-wrap-group | 
disp-formula | disp-formula-group | p | def-list | list | 
tex-math | mml:math | related-article | related-object | 
ack | disp-quote | speech | statement | verse-group)*, 
(notes | fn-group | glossary | ref-list | sig-block)*)


The following, in order:

This element may be contained in:

<abstract>, <ack>, <app>, <back>, <bio>, <body>, <book-front>, <boxed-text>, <notes>, <sec>, <trans-abstract>


<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>