diff --git a/eo-parser/src/main/antlr4/org/eolang/parser/Phi.g4 b/eo-parser/src/main/antlr4/org/eolang/parser/Phi.g4
index 2f34b51b61..a93b86390d 100644
--- a/eo-parser/src/main/antlr4/org/eolang/parser/Phi.g4
+++ b/eo-parser/src/main/antlr4/org/eolang/parser/Phi.g4
@@ -40,7 +40,7 @@ attribute
     : PHI
     | RHO
     | SIGMA
-    | VTX
+    | VERTEX
     | LABEL
     | alphaAttr
     ;
@@ -131,7 +131,8 @@ RHO : 'ρ'
 SIGMA
     : 'σ'
     ;
-VTX : 'ν'
+VERTEX
+    : 'ν'
     ;
 DELTA
     : 'Δ'
diff --git a/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java b/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java
index af835e7b9c..f1faefa355 100644
--- a/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java
+++ b/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java
@@ -216,13 +216,13 @@ public void enterBinding(final PhiParser.BindingContext ctx) {
     public void exitBinding(final PhiParser.BindingContext ctx) {
         if (this.objs.size() > this.packages.size()) {
             if (ctx.alphaBinding() != null) {
-                if (ctx.alphaBinding().attribute().VTX() != null) {
+                if (ctx.alphaBinding().attribute().VERTEX() != null) {
                     this.objects().remove();
                 } else {
                     this.objects().leave();
                 }
             } else if (ctx.emptyBinding() != null) {
-                if (ctx.emptyBinding().attribute().VTX() != null) {
+                if (ctx.emptyBinding().attribute().VERTEX() != null) {
                     this.objects().remove();
                 } else {
                     this.objects().leave();
@@ -251,7 +251,7 @@ public void enterAttribute(final PhiParser.AttributeContext ctx) {
             attr = "^";
         } else if (ctx.SIGMA() != null) {
             attr = "&";
-        } else if (ctx.VTX() != null) {
+        } else if (ctx.VERTEX() != null) {
             attr = "<";
         } else if (ctx.LABEL() != null) {
             attr = ctx.LABEL().getText();