diff --git a/lib/parser.js b/lib/parser.js
index 48c9f7f..a641ece 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -705,7 +705,7 @@ module.exports = (function() {
             if (s4 !== peg$FAILED) {
               s5 = peg$parse__();
               if (s5 !== peg$FAILED) {
-                s6 = peg$parseChoice();
+                s6 = peg$parseChoiceExpression();
                 if (s6 !== peg$FAILED) {
                   s7 = peg$parseEOS();
                   if (s7 !== peg$FAILED) {
@@ -744,11 +744,11 @@ module.exports = (function() {
       return s0;
     }
 
-    function peg$parseChoice() {
+    function peg$parseChoiceExpression() {
       var s0, s1, s2, s3, s4, s5, s6, s7;
 
       s0 = peg$currPos;
-      s1 = peg$parseSequence();
+      s1 = peg$parseSequenceExpression();
       if (s1 !== peg$FAILED) {
         s2 = [];
         s3 = peg$currPos;
@@ -764,7 +764,7 @@ module.exports = (function() {
           if (s5 !== peg$FAILED) {
             s6 = peg$parse__();
             if (s6 !== peg$FAILED) {
-              s7 = peg$parseSequence();
+              s7 = peg$parseSequenceExpression();
               if (s7 !== peg$FAILED) {
                 s4 = [s4, s5, s6, s7];
                 s3 = s4;
@@ -799,7 +799,7 @@ module.exports = (function() {
             if (s5 !== peg$FAILED) {
               s6 = peg$parse__();
               if (s6 !== peg$FAILED) {
-                s7 = peg$parseSequence();
+                s7 = peg$parseSequenceExpression();
                 if (s7 !== peg$FAILED) {
                   s4 = [s4, s5, s6, s7];
                   s3 = s4;
@@ -836,17 +836,17 @@ module.exports = (function() {
       return s0;
     }
 
-    function peg$parseSequence() {
+    function peg$parseSequenceExpression() {
       var s0, s1, s2, s3, s4, s5;
 
       s0 = peg$currPos;
-      s1 = peg$parseLabeled();
+      s1 = peg$parseLabeledExpression();
       if (s1 !== peg$FAILED) {
         s2 = [];
         s3 = peg$currPos;
         s4 = peg$parse__();
         if (s4 !== peg$FAILED) {
-          s5 = peg$parseLabeled();
+          s5 = peg$parseLabeledExpression();
           if (s5 !== peg$FAILED) {
             s4 = [s4, s5];
             s3 = s4;
@@ -863,7 +863,7 @@ module.exports = (function() {
           s3 = peg$currPos;
           s4 = peg$parse__();
           if (s4 !== peg$FAILED) {
-            s5 = peg$parseLabeled();
+            s5 = peg$parseLabeledExpression();
             if (s5 !== peg$FAILED) {
               s4 = [s4, s5];
               s3 = s4;
@@ -902,13 +902,13 @@ module.exports = (function() {
       }
       if (s0 === peg$FAILED) {
         s0 = peg$currPos;
-        s1 = peg$parseLabeled();
+        s1 = peg$parseLabeledExpression();
         if (s1 !== peg$FAILED) {
           s2 = [];
           s3 = peg$currPos;
           s4 = peg$parse__();
           if (s4 !== peg$FAILED) {
-            s5 = peg$parseLabeled();
+            s5 = peg$parseLabeledExpression();
             if (s5 !== peg$FAILED) {
               s4 = [s4, s5];
               s3 = s4;
@@ -925,7 +925,7 @@ module.exports = (function() {
             s3 = peg$currPos;
             s4 = peg$parse__();
             if (s4 !== peg$FAILED) {
-              s5 = peg$parseLabeled();
+              s5 = peg$parseLabeledExpression();
               if (s5 !== peg$FAILED) {
                 s4 = [s4, s5];
                 s3 = s4;
@@ -955,7 +955,7 @@ module.exports = (function() {
       return s0;
     }
 
-    function peg$parseLabeled() {
+    function peg$parseLabeledExpression() {
       var s0, s1, s2, s3, s4, s5;
 
       s0 = peg$currPos;
@@ -973,7 +973,7 @@ module.exports = (function() {
           if (s3 !== peg$FAILED) {
             s4 = peg$parse__();
             if (s4 !== peg$FAILED) {
-              s5 = peg$parsePrefixed();
+              s5 = peg$parsePrefixedExpression();
               if (s5 !== peg$FAILED) {
                 peg$reportedPos = s0;
                 s1 = peg$c15(s1, s5);
@@ -999,13 +999,13 @@ module.exports = (function() {
         s0 = peg$c0;
       }
       if (s0 === peg$FAILED) {
-        s0 = peg$parsePrefixed();
+        s0 = peg$parsePrefixedExpression();
       }
 
       return s0;
     }
 
-    function peg$parsePrefixed() {
+    function peg$parsePrefixedExpression() {
       var s0, s1, s2, s3;
 
       s0 = peg$currPos;
@@ -1019,7 +1019,7 @@ module.exports = (function() {
       if (s1 !== peg$FAILED) {
         s2 = peg$parse__();
         if (s2 !== peg$FAILED) {
-          s3 = peg$parseSuffixed();
+          s3 = peg$parseSuffixedExpression();
           if (s3 !== peg$FAILED) {
             peg$reportedPos = s0;
             s1 = peg$c18(s3);
@@ -1077,7 +1077,7 @@ module.exports = (function() {
           if (s1 !== peg$FAILED) {
             s2 = peg$parse__();
             if (s2 !== peg$FAILED) {
-              s3 = peg$parseSuffixed();
+              s3 = peg$parseSuffixedExpression();
               if (s3 !== peg$FAILED) {
                 peg$reportedPos = s0;
                 s1 = peg$c22(s3);
@@ -1135,7 +1135,7 @@ module.exports = (function() {
               if (s1 !== peg$FAILED) {
                 s2 = peg$parse__();
                 if (s2 !== peg$FAILED) {
-                  s3 = peg$parseSuffixed();
+                  s3 = peg$parseSuffixedExpression();
                   if (s3 !== peg$FAILED) {
                     peg$reportedPos = s0;
                     s1 = peg$c26(s3);
@@ -1153,7 +1153,7 @@ module.exports = (function() {
                 s0 = peg$c0;
               }
               if (s0 === peg$FAILED) {
-                s0 = peg$parseSuffixed();
+                s0 = peg$parseSuffixedExpression();
               }
             }
           }
@@ -1163,11 +1163,11 @@ module.exports = (function() {
       return s0;
     }
 
-    function peg$parseSuffixed() {
+    function peg$parseSuffixedExpression() {
       var s0, s1, s2, s3;
 
       s0 = peg$currPos;
-      s1 = peg$parsePrimary();
+      s1 = peg$parsePrimaryExpression();
       if (s1 !== peg$FAILED) {
         s2 = peg$parse__();
         if (s2 !== peg$FAILED) {
@@ -1196,7 +1196,7 @@ module.exports = (function() {
       }
       if (s0 === peg$FAILED) {
         s0 = peg$currPos;
-        s1 = peg$parsePrimary();
+        s1 = peg$parsePrimaryExpression();
         if (s1 !== peg$FAILED) {
           s2 = peg$parse__();
           if (s2 !== peg$FAILED) {
@@ -1225,7 +1225,7 @@ module.exports = (function() {
         }
         if (s0 === peg$FAILED) {
           s0 = peg$currPos;
-          s1 = peg$parsePrimary();
+          s1 = peg$parsePrimaryExpression();
           if (s1 !== peg$FAILED) {
             s2 = peg$parse__();
             if (s2 !== peg$FAILED) {
@@ -1253,7 +1253,7 @@ module.exports = (function() {
             s0 = peg$c0;
           }
           if (s0 === peg$FAILED) {
-            s0 = peg$parsePrimary();
+            s0 = peg$parsePrimaryExpression();
           }
         }
       }
@@ -1261,7 +1261,7 @@ module.exports = (function() {
       return s0;
     }
 
-    function peg$parsePrimary() {
+    function peg$parsePrimaryExpression() {
       var s0, s1, s2, s3, s4, s5, s6, s7;
 
       s0 = peg$currPos;
@@ -1350,7 +1350,7 @@ module.exports = (function() {
               if (s1 !== peg$FAILED) {
                 s2 = peg$parse__();
                 if (s2 !== peg$FAILED) {
-                  s3 = peg$parseChoice();
+                  s3 = peg$parseChoiceExpression();
                   if (s3 !== peg$FAILED) {
                     s4 = peg$parse__();
                     if (s4 !== peg$FAILED) {
diff --git a/spec/parser.spec.js b/spec/parser.spec.js
index e21cfad..b0b1bde 100644
--- a/spec/parser.spec.js
+++ b/spec/parser.spec.js
@@ -232,8 +232,8 @@ describe("PEG.js grammar parser", function() {
     );
   });
 
-  /* Canonical Choice is "\"abcd\" / \"efgh\" / \"ijkl\"". */
-  it("parses Choice", function() {
+  /* Canonical ChoiceExpression is "\"abcd\" / \"efgh\" / \"ijkl\"". */
+  it("parses ChoiceExpression", function() {
     expect('start = "abcd" "efgh" "ijkl"').toParseAs(
       oneRuleGrammar(sequenceOfLiterals)
     );
@@ -257,8 +257,8 @@ describe("PEG.js grammar parser", function() {
     }));
   });
 
-  /* Canonical Sequence is "\"abcd\" \"efgh\" \"ijkl\"". */
-  it("parses Sequence", function() {
+  /* Canonical SequenceExpression is "\"abcd\" \"efgh\" \"ijkl\"". */
+  it("parses SequenceExpression", function() {
     expect('start = a:"abcd" { code }').toParseAs(
       oneRuleGrammar({ type: "action", expression: labeledAbcd, code: " code " })
     );
@@ -291,16 +291,16 @@ describe("PEG.js grammar parser", function() {
     );
   });
 
-  /* Canonical Labeled is "label:\"abcd\"". */
-  it("parses Labeled", function() {
+  /* Canonical LabeledExpression is "label:\"abcd\"". */
+  it("parses LabeledExpression", function() {
     expect('start = label:!"abcd"'  ).toParseAs(oneRuleGrammar(labeledSimpleNotLiteral));
     expect('start = label\n:!"abcd"').toParseAs(oneRuleGrammar(labeledSimpleNotLiteral));
     expect('start = label:\n!"abcd"').toParseAs(oneRuleGrammar(labeledSimpleNotLiteral));
     expect('start = !"abcd"'        ).toParseAs(oneRuleGrammar(simpleNotLiteral));
   });
 
-  /* Canonical Prefixed is "!\"abcd\"". */
-  it("parses Prefixed", function() {
+  /* Canonical PrefixedExpression is "!\"abcd\"". */
+  it("parses PrefixedExpression", function() {
     expect('start = $"abcd"?'   ).toParseAs(oneRuleGrammar(textOptionalLiteral));
     expect('start = $\n"abcd"?' ).toParseAs(oneRuleGrammar(textOptionalLiteral));
     expect('start = &{ code }'  ).toParseAs(oneRuleGrammar(semanticAnd));
@@ -314,8 +314,8 @@ describe("PEG.js grammar parser", function() {
     expect('start = "abcd"?'    ).toParseAs(oneRuleGrammar(optionalLiteral));
   });
 
-  /* Canonical Suffixed is "\"abcd\"?". */
-  it("parses Suffixed", function() {
+  /* Canonical SuffixedExpression is "\"abcd\"?". */
+  it("parses SuffixedExpression", function() {
     expect('start = "abcd"?'  ).toParseAs(oneRuleGrammar(optionalLiteral));
     expect('start = "abcd"\n?').toParseAs(oneRuleGrammar(optionalLiteral));
     expect('start = "abcd"*'  ).toParseAs(oneRuleGrammar(zeroOrMoreLiteral));
@@ -325,8 +325,8 @@ describe("PEG.js grammar parser", function() {
     expect('start = "abcd"'   ).toParseAs(literalGrammar("abcd"));
   });
 
-  /* Canonical Primary is "\"abcd\"". */
-  it("parses Primary", function() {
+  /* Canonical PrimaryExpression is "\"abcd\"". */
+  it("parses PrimaryExpression", function() {
     expect('start = a'         ).toParseAs(ruleRefGrammar("a"));
     expect('start = "abcd"'    ).toParseAs(literalGrammar("abcd"));
     expect('start = [a-d]'     ).toParseAs(classGrammar([["a", "d"]], "[a-d]"));
diff --git a/src/parser.pegjs b/src/parser.pegjs
index 166d9e5..cffb07a 100644
--- a/src/parser.pegjs
+++ b/src/parser.pegjs
@@ -67,17 +67,17 @@ Rule
     }
 
 Expression
-  = Choice
+  = ChoiceExpression
 
-Choice
-  = first:Sequence rest:(__ "/" __ Sequence)* {
+ChoiceExpression
+  = first:SequenceExpression rest:(__ "/" __ SequenceExpression)* {
       return rest.length > 0
         ? { type: "choice", alternatives: buildList(first, rest, 3) }
         : first;
     }
 
-Sequence
-  = first:Labeled rest:(__ Labeled)* __ code:CodeBlock {
+SequenceExpression
+  = first:LabeledExpression rest:(__ LabeledExpression)* __ code:CodeBlock {
       var expression = rest.length > 0
         ? { type: "sequence", elements: buildList(first, rest, 1) }
         : first;
@@ -87,24 +87,24 @@ Sequence
         code:       code
       };
     }
-  / first:Labeled rest:(__ Labeled)* {
+  / first:LabeledExpression rest:(__ LabeledExpression)* {
       return rest.length > 0
         ? { type: "sequence", elements: buildList(first, rest, 1) }
         : first;
     }
 
-Labeled
-  = label:Identifier __ ":" __ expression:Prefixed {
+LabeledExpression
+  = label:Identifier __ ":" __ expression:PrefixedExpression {
       return {
         type:       "labeled",
         label:      label,
         expression: expression
       };
     }
-  / Prefixed
+  / PrefixedExpression
 
-Prefixed
-  = "$" __ expression:Suffixed {
+PrefixedExpression
+  = "$" __ expression:SuffixedExpression {
       return {
         type:       "text",
         expression: expression
@@ -116,7 +116,7 @@ Prefixed
         code: code
       };
     }
-  / "&" __ expression:Suffixed {
+  / "&" __ expression:SuffixedExpression {
       return {
         type:       "simple_and",
         expression: expression
@@ -128,36 +128,36 @@ Prefixed
         code: code
       };
     }
-  / "!" __ expression:Suffixed {
+  / "!" __ expression:SuffixedExpression {
       return {
         type:       "simple_not",
         expression: expression
       };
     }
-  / Suffixed
+  / SuffixedExpression
 
-Suffixed
-  = expression:Primary __ "?" {
+SuffixedExpression
+  = expression:PrimaryExpression __ "?" {
       return {
         type:       "optional",
         expression: expression
       };
     }
-  / expression:Primary __ "*" {
+  / expression:PrimaryExpression __ "*" {
       return {
         type:       "zero_or_more",
         expression: expression
       };
     }
-  / expression:Primary __ "+" {
+  / expression:PrimaryExpression __ "+" {
       return {
         type:       "one_or_more",
         expression: expression
       };
     }
-  / Primary
+  / PrimaryExpression
 
-Primary
+PrimaryExpression
   = name:IdentifierName !(__ (StringLiteral __)? "=") {
       return {
         type: "rule_ref",