primary — The primary word or phrase under which an index term should be sorted
primary ::=
abbrevaccelacronymaltanchorannotationapplicationauthorbibliorefcitationcitebiblioidciterefentrycitetitleclassnamecodecommandcomputeroutputconstantcorefdatabasedateeditoremailemphasis (db.emphasis)envarerrorcodeerrornameerrortexterrortypeexceptionnamefilenamefirsttermfootnotefootnoterefforeignphrasefunctionglosstermguibuttonguiiconguilabelguimenuguimenuitemguisubmenuhardwarehtml:buttonhtml:fieldsethtml:inputhtml:labelhtml:selecthtml:textareaindexterm (db.indexterm.endofrange)indexterm (db.indexterm.singular)indexterm (db.indexterm.startofrange)initializerinlineequationinlinemediaobjectinterfacenamekeycapkeycodekeycombokeysymlinkliteralmarkupmenuchoicemethodnamemodifiermousebuttonnonterminalolinkooclassooexceptionoointerfaceoptionoptionalorgnamepackageparameterpersonnamephrase (db.phrase)productnameproductnumberpromptpropertyquoteremarkreplaceablereturnvalueshortcutsubscriptsuperscriptsymbolsystemitemtagtermdeftokentrademarktypeuriuserinputvarnamewordaswordxrefIn an IndexTerm, Primary identifies the most
significant word or words in the entry.  All IndexTerms must
have a Primary.
Suppressed. This element provides data for processing but it is not rendered in the primary flow of text.
These elements contain primary: indexterm (db.indexterm.singular), indexterm (db.indexterm.startofrange).
The following elements occur in primary: text, abbrev, accel, acronym, alt, anchor, annotation, application, author, biblioref, citation, citebiblioid, citerefentry, citetitle, classname, code, command, computeroutput, constant, coref, database, date, editor, email, emphasis (db.emphasis), envar, errorcode, errorname, errortext, errortype, exceptionname, filename, firstterm, footnote, footnoteref, foreignphrase, function, glossterm, guibutton, guiicon, guilabel, guimenu, guimenuitem, guisubmenu, hardware, html:button, html:fieldset, html:input, html:label, html:select, html:textarea, indexterm (db.indexterm.endofrange), indexterm (db.indexterm.singular), indexterm (db.indexterm.startofrange), initializer, inlineequation, inlinemediaobject, interfacename, keycap, keycode, keycombo, keysym, link, literal, markup, menuchoice, methodname, modifier, mousebutton, nonterminal, olink, ooclass, ooexception, oointerface, option, optional, orgname, package, parameter, personname, phrase (db.phrase), productname, productnumber, prompt, property, quote, remark, replaceable, returnvalue, shortcut, subscript, superscript, symbol, systemitem, tag, termdef, token, trademark, type, uri, userinput, varname, wordasword, xref.
indexentry, indexterm, primaryie, secondary, secondaryie, see, seealso, seealsoie, seeie, tertiary, tertiaryie