diff --git a/packages/mermaid/src/diagrams/er/parser/erDiagram.jison b/packages/mermaid/src/diagrams/er/parser/erDiagram.jison
index 1134ee889fc..2a49ff115d2 100644
--- a/packages/mermaid/src/diagrams/er/parser/erDiagram.jison
+++ b/packages/mermaid/src/diagrams/er/parser/erDiagram.jison
@@ -67,8 +67,10 @@ accDescr\s*"{"\s*                                { this.begin("acc_descr_multili
 "one"                           return 'ONLY_ONE';
 "only one"                      return 'ONLY_ONE';
 [0-9]+\.[0-9]+                  return 'DECIMAL_NUM';
-"1"(?=\s+[A-Za-z_"'])           return 'ONLY_ONE';
-"1"(?=\s+[0-9])                 return 'ONLY_ONE';
+"1"(?=\s+(?:1|many|one|zero|only)\s+to\b) return 'ENTITY_ONE';
+"1"(?=\s+(?!(?:many|one|only|zero|optionally|to)\b)[A-Za-z_"'])           return 'ONLY_ONE';
+"1"(?=\s+to\b)                  return 'ONLY_ONE';
+"1"(?=\s+[0-9]+\s*:)            return 'ONLY_ONE';
 "1"(?=(\-\-|\.\.|\.\-|\-\.))    return 'ONLY_ONE';
 "1"                             return 'ENTITY_ONE';
 [0-9]+                          return 'NUM';
@@ -301,4 +303,4 @@ role
     | 'UNICODE_TEXT'  { $$ = $1; }
     ;
 
-%%
\ No newline at end of file
+%%
diff --git a/packages/mermaid/src/diagrams/er/parser/erDiagram.spec.js b/packages/mermaid/src/diagrams/er/parser/erDiagram.spec.js
index 54bb7c2ca3e..026ae2a40e0 100644
--- a/packages/mermaid/src/diagrams/er/parser/erDiagram.spec.js
+++ b/packages/mermaid/src/diagrams/er/parser/erDiagram.spec.js
@@ -820,6 +820,43 @@ describe('when parsing ER diagram it...', function () {
     expect(rels[0].relSpec.relType).toBe(erDb.Identification.IDENTIFYING);
   });
 
+  it('should allow numeric entity identifier "1" on left side with cardinality 1', function () {
+    // This should parse without throwing - the fix for #7472 broke left-side numeric identifiers
+    erDiagram.parser.parse('erDiagram\n1 1 to many SomeEntity: label');
+    const entities = erDb.getEntities();
+    const rels = erDb.getRelationships();
+
+    // Verify both entities were created
+    expect(entities.size).toBe(2);
+    expect(entities.has('1')).toBe(true);
+    expect(entities.has('SomeEntity')).toBe(true);
+
+    // Verify one relationship was created
+    expect(rels.length).toBe(1);
+
+    // For "1 1 to many SomeEntity:": first "1" is entity name, second "1" is cardinality (ONLY_ONE)
+    // So cardB = 1 (ONLY_ONE), cardA = many (ZERO_OR_MORE)
+    expect(rels[0].relSpec.cardA).toBe(erDb.Cardinality.ZERO_OR_MORE); // "many"
+    expect(rels[0].relSpec.cardB).toBe(erDb.Cardinality.ONLY_ONE); // second "1"
+
+    // Verify relationship type: "to" means IDENTIFYING
+    expect(rels[0].relSpec.relType).toBe(erDb.Identification.IDENTIFYING);
+  });
+
+  it('should allow numeric entity identifier "1" on left side with many cardinality', function () {
+    erDiagram.parser.parse('erDiagram\n1 many to many SomeEntity: label');
+    const entities = erDb.getEntities();
+    const rels = erDb.getRelationships();
+
+    expect(entities.size).toBe(2);
+    expect(entities.has('1')).toBe(true);
+    expect(entities.has('SomeEntity')).toBe(true);
+    expect(rels.length).toBe(1);
+    expect(rels[0].relSpec.cardA).toBe(erDb.Cardinality.ZERO_OR_MORE);
+    expect(rels[0].relSpec.cardB).toBe(erDb.Cardinality.ZERO_OR_MORE);
+    expect(rels[0].relSpec.relType).toBe(erDb.Identification.IDENTIFYING);
+  });
+
   it('should represent identifying relationships properly', function () {
     erDiagram.parser.parse('erDiagram\nHOUSE ||--|{ ROOM : contains');
     const rels = erDb.getRelationships();