@@ -224,7 +224,7 @@ are a few of note:
 
 *   [github_flavored_markdown](https://godoc.org/github.com/shurcooL/github_flavored_markdown):
     provides a GitHub Flavored Markdown renderer with fenced code block
-    highlighting, clickable header anchor links.
+    highlighting, clickable heading anchor links.
 
     It's not customizable, and its goal is to produce HTML output
     equivalent to the [GitHub Markdown API endpoint](https://developer.github.com/v3/markdown/#render-a-markdown-document-in-raw-mode),

@@ -43,14 +43,14 @@ p.nesting++
 
 	// parse out one block-level construct at a time
 	for len(data) > 0 {
-		// prefixed header:
+		// prefixed heading:
 		//
-		// # Header 1
-		// ## Header 2
+		// # Heading 1
+		// ## Heading 2
 		// ...
-		// ###### Header 6
-		if p.isPrefixHeader(data) {
-			data = data[p.prefixHeader(data):]
+		// ###### Heading 6
+		if p.isPrefixHeading(data) {
+			data = data[p.prefixHeading(data):]
 			continue
 		}
 
@@ -190,7 +190,7 @@ }
 		}
 
 		// anything else must look like a normal paragraph
-		// note: this finds underlined headers, too
+		// note: this finds underlined headings, too
 		data = data[p.paragraph(data):]
 	}
 
@@ -204,12 +204,12 @@ container.content = content
 	return container
 }
 
-func (p *parser) isPrefixHeader(data []byte) bool {
+func (p *parser) isPrefixHeading(data []byte) bool {
 	if data[0] != '#' {
 		return false
 	}
 
-	if p.flags&SpaceHeaders != 0 {
+	if p.flags&SpaceHeadings != 0 {
 		level := 0
 		for level < 6 && level < len(data) && data[level] == '#' {
 			level++
@@ -221,7 +221,7 @@ }
 	return true
 }
 
-func (p *parser) prefixHeader(data []byte) int {
+func (p *parser) prefixHeading(data []byte) int {
 	level := 0
 	for level < 6 && level < len(data) && data[level] == '#' {
 		level++
@@ -230,14 +230,14 @@ i := skipChar(data, level, ' ')
 	end := skipUntilChar(data, i, '\n')
 	skip := end
 	id := ""
-	if p.flags&HeaderIDs != 0 {
+	if p.flags&HeadingIDs != 0 {
 		j, k := 0, 0
-		// find start/end of header id
+		// find start/end of heading id
 		for j = i; j < end-1 && (data[j] != '{' || data[j+1] != '#'); j++ {
 		}
 		for k = j + 1; k < end && data[k] != '}'; k++ {
 		}
-		// extract header id iff found
+		// extract heading id iff found
 		if j < end && k < end {
 			id = string(data[j+2 : k])
 			end = j
@@ -257,18 +257,18 @@ for end > 0 && data[end-1] == ' ' {
 		end--
 	}
 	if end > i {
-		if id == "" && p.flags&AutoHeaderIDs != 0 {
+		if id == "" && p.flags&AutoHeadingIDs != 0 {
 			id = sanitized_anchor_name.Create(string(data[i:end]))
 		}
-		block := p.addBlock(Header, data[i:end])
-		block.HeaderID = id
+		block := p.addBlock(Heading, data[i:end])
+		block.HeadingID = id
 		block.Level = level
 	}
 	return skip
 }
 
-func (p *parser) isUnderlinedHeader(data []byte) int {
-	// test of level 1 header
+func (p *parser) isUnderlinedHeading(data []byte) int {
+	// test of level 1 heading
 	if data[0] == '=' {
 		i := skipChar(data, 1, '=')
 		i = skipChar(data, i, ' ')
@@ -278,7 +278,7 @@ }
 		return 0
 	}
 
-	// test of level 2 header
+	// test of level 2 heading
 	if data[0] == '-' {
 		i := skipChar(data, 1, '-')
 		i = skipChar(data, i, ' ')
@@ -308,7 +308,7 @@ data = bytes.Join(splitData[0:i], []byte("\n"))
 	consumed := len(data)
 	data = bytes.TrimPrefix(data, []byte("% "))
 	data = bytes.Replace(data, []byte("\n% "), []byte("\n"), -1)
-	block := p.addBlock(Header, data)
+	block := p.addBlock(Heading, data)
 	block.Level = 1
 	block.IsTitleblock = true
 
@@ -1301,9 +1301,9 @@ if sublist == 0 {
 				sublist = raw.Len()
 			}
 
-		// is this a nested prefix header?
-		case p.isPrefixHeader(chunk):
-			// if the header is not indented, it is not nested in the list
+		// is this a nested prefix heading?
+		case p.isPrefixHeading(chunk):
+			// if the heading is not indented, it is not nested in the list
 			// and thus ends the list
 			if containsBlankLine && indent < 4 {
 				*flags |= ListItemEndOfList
@@ -1445,9 +1445,9 @@ p.renderParagraph(data[:i])
 			return i + n
 		}
 
-		// an underline under some text marks a header, so our paragraph ended on prev line
+		// an underline under some text marks a heading, so our paragraph ended on prev line
 		if i > 0 {
-			if level := p.isUnderlinedHeader(current); level > 0 {
+			if level := p.isUnderlinedHeading(current); level > 0 {
 				// render the paragraph
 				p.renderParagraph(data[:prev])
 
@@ -1461,13 +1461,13 @@ eol--
 				}
 
 				id := ""
-				if p.flags&AutoHeaderIDs != 0 {
+				if p.flags&AutoHeadingIDs != 0 {
 					id = sanitized_anchor_name.Create(string(data[prev:eol]))
 				}
 
-				block := p.addBlock(Header, data[prev:eol])
+				block := p.addBlock(Heading, data[prev:eol])
 				block.Level = level
-				block.HeaderID = id
+				block.HeadingID = id
 
 				// find the end of the underline
 				for i < len(data) && data[i] != '\n' {
@@ -1486,8 +1486,8 @@ return i
 			}
 		}
 
-		// if there's a prefixed header or a horizontal rule after this, paragraph is over
-		if p.isPrefixHeader(current) || p.isHRule(current) {
+		// if there's a prefixed heading or a horizontal rule after this, paragraph is over
+		if p.isPrefixHeading(current) || p.isHRule(current) {
 			p.renderParagraph(data[:i])
 			return i
 		}

@@ -144,7 +144,7 @@ "*   List\n    * Nested list\n    # Nested header\n",
 		"<ul>\n<li><p>List</p>\n\n<ul>\n<li><p>Nested list</p>\n\n" +
 			"<h1>Nested header</h1></li>\n</ul></li>\n</ul>\n",
 	}
-	doTestsBlock(t, tests, SpaceHeaders)
+	doTestsBlock(t, tests, SpaceHeadings)
 }
 
 func TestPrefixHeaderIdExtension(t *testing.T) {
@@ -204,7 +204,7 @@ "*   List\n    * Nested list\n    # Nested header {#someid}\n",
 		"<ul>\n<li><p>List</p>\n\n<ul>\n<li><p>Nested list</p>\n\n" +
 			"<h1 id=\"someid\">Nested header</h1></li>\n</ul></li>\n</ul>\n",
 	}
-	doTestsBlock(t, tests, HeaderIDs)
+	doTestsBlock(t, tests, HeadingIDs)
 }
 
 func TestPrefixHeaderIdExtensionWithPrefixAndSuffix(t *testing.T) {
@@ -248,12 +248,12 @@ "<h1 id=\"PRE:someid:POST\">Nested header</h1></li>\n</ul></li>\n</ul>\n",
 	}
 
 	parameters := HTMLRendererParameters{
-		HeaderIDPrefix: "PRE:",
-		HeaderIDSuffix: ":POST",
+		HeadingIDPrefix: "PRE:",
+		HeadingIDSuffix: ":POST",
 	}
 
 	doTestsParam(t, tests, TestParams{
-		Options:                Options{Extensions: HeaderIDs},
+		Options:                Options{Extensions: HeadingIDs},
 		HTMLFlags:              UseXHTML,
 		HTMLRendererParameters: parameters,
 	})
@@ -307,7 +307,7 @@ 
 		"# Header\n\n# Header 1\n\n# Header\n\n# Header",
 		"<h1 id=\"header\">Header</h1>\n\n<h1 id=\"header-1\">Header 1</h1>\n\n<h1 id=\"header-1-1\">Header</h1>\n\n<h1 id=\"header-1-2\">Header</h1>\n",
 	}
-	doTestsBlock(t, tests, AutoHeaderIDs)
+	doTestsBlock(t, tests, AutoHeadingIDs)
 }
 
 func TestPrefixAutoHeaderIdExtensionWithPrefixAndSuffix(t *testing.T) {
@@ -360,12 +360,12 @@ "<h1 id=\"PRE:header:POST\">Header</h1>\n\n<h1 id=\"PRE:header-1:POST\">Header 1</h1>\n\n<h1 id=\"PRE:header-1-1:POST\">Header</h1>\n\n<h1 id=\"PRE:header-1-2:POST\">Header</h1>\n",
 	}
 
 	parameters := HTMLRendererParameters{
-		HeaderIDPrefix: "PRE:",
-		HeaderIDSuffix: ":POST",
+		HeadingIDPrefix: "PRE:",
+		HeadingIDSuffix: ":POST",
 	}
 
 	doTestsParam(t, tests, TestParams{
-		Options:                Options{Extensions: AutoHeaderIDs},
+		Options:                Options{Extensions: AutoHeadingIDs},
 		HTMLFlags:              UseXHTML,
 		HTMLRendererParameters: parameters,
 	})
@@ -376,7 +376,7 @@ var tests = []string{
 		"# Header\n\n# Header {#header}\n\n# Header 1",
 		"<h1 id=\"header\">Header</h1>\n\n<h1 id=\"header-1\">Header</h1>\n\n<h1 id=\"header-1-1\">Header 1</h1>\n",
 	}
-	doTestsBlock(t, tests, AutoHeaderIDs|HeaderIDs)
+	doTestsBlock(t, tests, AutoHeadingIDs|HeadingIDs)
 }
 
 func TestUnderlineHeaders(t *testing.T) {
@@ -476,7 +476,7 @@ 
 		"Header 1\n========\n\nHeader 1\n========\n",
 		"<h1 id=\"header-1\">Header 1</h1>\n\n<h1 id=\"header-1-1\">Header 1</h1>\n",
 	}
-	doTestsBlock(t, tests, AutoHeaderIDs)
+	doTestsBlock(t, tests, AutoHeadingIDs)
 }
 
 func TestHorizontalRule(t *testing.T) {

@@ -80,11 +80,11 @@ // Show this text inside the <a> tag for a footnote return link, if the
 	// HTML_FOOTNOTE_RETURN_LINKS flag is enabled. If blank, the string
 	// <sup>[return]</sup> is used.
 	FootnoteReturnLinkContents string
-	// If set, add this text to the front of each Header ID, to ensure
+	// If set, add this text to the front of each Heading ID, to ensure
 	// uniqueness.
-	HeaderIDPrefix string
-	// If set, add this text to the back of each Header ID, to ensure uniqueness.
-	HeaderIDSuffix string
+	HeadingIDPrefix string
+	// If set, add this text to the back of each Heading ID, to ensure uniqueness.
+	HeadingIDSuffix string
 
 	Title string // Document title (used if CompletePage is set)
 	CSS   string // Optional CSS file URL (used if CompletePage is set)
@@ -101,8 +101,8 @@ HTMLRendererParameters
 
 	closeTag string // how to end singleton tags: either " />" or ">"
 
-	// Track header IDs to prevent ID collision in a single generation.
-	headerIDs map[string]int
+	// Track heading IDs to prevent ID collision in a single generation.
+	headingIDs map[string]int
 
 	lastOutputLen int
 	disableTags   int
@@ -131,8 +131,8 @@ 
 	return &HTMLRenderer{
 		HTMLRendererParameters: params,
 
-		closeTag:  closeTag,
-		headerIDs: make(map[string]int),
+		closeTag:   closeTag,
+		headingIDs: make(map[string]int),
 
 		sr: NewSmartypantsRenderer(params.Flags),
 	}
@@ -238,20 +238,20 @@ 
 	return false
 }
 
-func (r *HTMLRenderer) ensureUniqueHeaderID(id string) string {
-	for count, found := r.headerIDs[id]; found; count, found = r.headerIDs[id] {
+func (r *HTMLRenderer) ensureUniqueHeadingID(id string) string {
+	for count, found := r.headingIDs[id]; found; count, found = r.headingIDs[id] {
 		tmp := fmt.Sprintf("%s-%d", id, count+1)
 
-		if _, tmpFound := r.headerIDs[tmp]; !tmpFound {
-			r.headerIDs[id] = count + 1
+		if _, tmpFound := r.headingIDs[tmp]; !tmpFound {
+			r.headingIDs[id] = count + 1
 			id = tmp
 		} else {
 			id = id + "-1"
 		}
 	}
 
-	if _, found := r.headerIDs[id]; !found {
-		r.headerIDs[id] = 0
+	if _, found := r.headingIDs[id]; !found {
+		r.headingIDs[id] = 0
 	}
 
 	return id
@@ -457,7 +457,7 @@ footnotesDivBytes      = []byte("\n<div class=\"footnotes\">\n\n")
 	footnotesCloseDivBytes = []byte("\n</div>\n")
 )
 
-func headerTagsFromLevel(level int) ([]byte, []byte) {
+func headingTagsFromLevel(level int) ([]byte, []byte) {
 	switch level {
 	case 1:
 		return h1Tag, h1CloseTag
@@ -619,7 +619,7 @@ // TODO: untangle this clusterfuck about when the newlines need
 			// to be added and when not.
 			if node.Prev != nil {
 				switch node.Prev.Type {
-				case HTMLBlock, List, Paragraph, Header, CodeBlock, BlockQuote, HorizontalRule:
+				case HTMLBlock, List, Paragraph, Heading, CodeBlock, BlockQuote, HorizontalRule:
 					r.cr(w)
 				}
 			}
@@ -648,19 +648,19 @@ }
 		r.cr(w)
 		r.out(w, node.Literal)
 		r.cr(w)
-	case Header:
-		openTag, closeTag := headerTagsFromLevel(node.Level)
+	case Heading:
+		openTag, closeTag := headingTagsFromLevel(node.Level)
 		if entering {
 			if node.IsTitleblock {
 				attrs = append(attrs, `class="title"`)
 			}
-			if node.HeaderID != "" {
-				id := r.ensureUniqueHeaderID(node.HeaderID)
-				if r.HeaderIDPrefix != "" {
-					id = r.HeaderIDPrefix + id
+			if node.HeadingID != "" {
+				id := r.ensureUniqueHeadingID(node.HeadingID)
+				if r.HeadingIDPrefix != "" {
+					id = r.HeadingIDPrefix + id
 				}
-				if r.HeaderIDSuffix != "" {
-					id = id + r.HeaderIDSuffix
+				if r.HeadingIDSuffix != "" {
+					id = id + r.HeadingIDSuffix
 				}
 				attrs = append(attrs, fmt.Sprintf(`id="%s"`, id))
 			}
@@ -870,15 +870,15 @@ 
 func (r *HTMLRenderer) writeTOC(w *bytes.Buffer, ast *Node) {
 	buf := bytes.Buffer{}
 
-	inHeader := false
+	inHeading := false
 	tocLevel := 0
-	headerCount := 0
+	headingCount := 0
 
 	ast.Walk(func(node *Node, entering bool) WalkStatus {
-		if node.Type == Header && !node.HeaderData.IsTitleblock {
-			inHeader = entering
+		if node.Type == Heading && !node.HeadingData.IsTitleblock {
+			inHeading = entering
 			if entering {
-				node.HeaderID = fmt.Sprintf("toc_%d", headerCount)
+				node.HeadingID = fmt.Sprintf("toc_%d", headingCount)
 				if node.Level == tocLevel {
 					buf.WriteString("</li>\n\n<li>")
 				} else if node.Level < tocLevel {
@@ -894,15 +894,15 @@ buf.WriteString("\n<ul>\n<li>")
 					}
 				}
 
-				fmt.Fprintf(&buf, `<a href="#toc_%d">`, headerCount)
-				headerCount++
+				fmt.Fprintf(&buf, `<a href="#toc_%d">`, headingCount)
+				headingCount++
 			} else {
 				buf.WriteString("</a>")
 			}
 			return GoToNext
 		}
 
-		if inHeader {
+		if inHeading {
 			return r.RenderNode(&buf, node, entering)
 		}
 

@@ -36,14 +36,14 @@ FencedCode                                    // Render fenced code blocks
 	Autolink                                      // Detect embedded URLs that are not explicitly marked
 	Strikethrough                                 // Strikethrough text using ~~test~~
 	LaxHTMLBlocks                                 // Loosen up HTML block parsing rules
-	SpaceHeaders                                  // Be strict about prefix header rules
+	SpaceHeadings                                 // Be strict about prefix heading rules
 	HardLineBreak                                 // Translate newlines into line breaks
 	TabSizeEight                                  // Expand tabs to eight spaces instead of four
 	Footnotes                                     // Pandoc-style footnotes
 	NoEmptyLineBeforeBlock                        // No need to insert an empty line to start a (code, quote, ordered list, unordered list) block
-	HeaderIDs                                     // specify header IDs  with {#id}
+	HeadingIDs                                    // specify heading IDs  with {#id}
 	Titleblock                                    // Titleblock ala pandoc
-	AutoHeaderIDs                                 // Create the header ID from the text
+	AutoHeadingIDs                                // Create the heading ID from the text
 	BackslashLineBreak                            // Translate trailing backslashes into line breaks
 	DefinitionLists                               // Render definition lists
 
@@ -51,7 +51,7 @@ CommonHTMLFlags HTMLFlags = UseXHTML | Smartypants |
 		SmartypantsFractions | SmartypantsDashes | SmartypantsLatexDashes
 
 	CommonExtensions Extensions = NoIntraEmphasis | Tables | FencedCode |
-		Autolink | Strikethrough | SpaceHeaders | HeaderIDs |
+		Autolink | Strikethrough | SpaceHeadings | HeadingIDs |
 		BackslashLineBreak | DefinitionLists
 )
 
@@ -310,9 +310,9 @@ // * Autolinking
 //
 // * Strikethrough support
 //
-// * Strict header parsing
+// * Strict heading parsing
 //
-// * Custom Header IDs
+// * Custom Heading IDs
 func MarkdownCommon(input []byte) []byte {
 	// set up the HTML renderer
 	renderer := NewHTMLRenderer(HTMLRendererParameters{
@@ -392,7 +392,7 @@ p.finalize(p.tip)
 	}
 	// Walk the tree again and process inline markdown in each block
 	p.doc.Walk(func(node *Node, entering bool) WalkStatus {
-		if node.Type == Paragraph || node.Type == Header || node.Type == TableCell {
+		if node.Type == Paragraph || node.Type == Heading || node.Type == TableCell {
 			p.inline(node, node.content)
 			node.content = nil
 		}
@@ -433,7 +433,7 @@ above := block.Parent
 	finalizeList(block)
 	p.tip = above
 	block.Walk(func(node *Node, entering bool) WalkStatus {
-		if node.Type == Paragraph || node.Type == Header {
+		if node.Type == Paragraph || node.Type == Heading {
 			p.inline(node, node.content)
 			node.content = nil
 		}

@@ -17,7 +17,7 @@ BlockQuote
 	List
 	Item
 	Paragraph
-	Header
+	Heading
 	HorizontalRule
 	Emph
 	Strong
@@ -44,7 +44,7 @@ BlockQuote:     "BlockQuote",
 	List:           "List",
 	Item:           "Item",
 	Paragraph:      "Paragraph",
-	Header:         "Header",
+	Heading:        "Heading",
 	HorizontalRule: "HorizontalRule",
 	Emph:           "Emph",
 	Strong:         "Strong",
@@ -102,10 +102,10 @@ IsHeader bool           // This tells if it's under the header row
 	Align    CellAlignFlags // This holds the value for align attribute
 }
 
-// HeaderData contains fields relevant to a Header node type.
-type HeaderData struct {
+// HeadingData contains fields relevant to a Heading node type.
+type HeadingData struct {
 	Level        int    // This holds the heading level number
-	HeaderID     string // This might hold header ID, if present
+	HeadingID    string // This might hold heading ID, if present
 	IsTitleblock bool   // Specifies whether it's a title block
 }
 
@@ -122,7 +122,7 @@ Next       *Node    // Next sibling; nil if it's the last child
 
 	Literal []byte // Text contents of the leaf nodes
 
-	HeaderData    // Populated if Type is Header
+	HeadingData   // Populated if Type is Heading
 	ListData      // Populated if Type is List
 	CodeBlockData // Populated if Type is CodeBlock
 	LinkData      // Populated if Type is Link
@@ -211,7 +211,7 @@ case Item:
 		fallthrough
 	case Paragraph:
 		fallthrough
-	case Header:
+	case Heading:
 		fallthrough
 	case Emph:
 		fallthrough