diff --git a/pysd/py_backend/external.py b/pysd/py_backend/external.py
index bd64bdcb..f4104b1f 100644
--- a/pysd/py_backend/external.py
+++ b/pysd/py_backend/external.py
@@ -94,8 +94,9 @@ class External(object):
         fail, but it may be used to check the quality of the data.
     file: str
         File name from which the data is read.
-    sheet: str
-        Sheet name from which the data is read.
+    tab: str
+        Tab name from which the data is read. If file type is not a
+        spreadsheet this will be used as a separator.
 
     """
     missing = "warning"
diff --git a/pysd/py_backend/model.py b/pysd/py_backend/model.py
index 2db13ad7..5d97eb1c 100644
--- a/pysd/py_backend/model.py
+++ b/pysd/py_backend/model.py
@@ -753,7 +753,7 @@ def __include_for_serialization(self, ext, py_name_clean, data, metadata,
             for col in self._doc.columns
         }
         var_meta["files"] = ";".join(ext.files)
-        var_meta["sheets"] = ";".join(ext.sheets)
+        var_meta["tabs"] = ";".join(ext.tabs)
         var_meta["cells"] = ";".join(ext.cells)
         # TODO: add also time_row_or_cols
 
diff --git a/pysd/translators/structures/abstract_expressions.py b/pysd/translators/structures/abstract_expressions.py
index 07e02dec..5af36388 100644
--- a/pysd/translators/structures/abstract_expressions.py
+++ b/pysd/translators/structures/abstract_expressions.py
@@ -558,7 +558,8 @@ class GetLookupsStructure(AbstractSyntax):
     file: str
         The file path where the data is.
     tab: str
-        The sheetname where the data is.
+        Tab name from which the data is read. If file type is not a
+        spreadsheet this will be used as a separator.
     x_row_or_col: str
         The pointer to the cell or cellrange name that defines the
         interpolation series data.
@@ -587,7 +588,8 @@ class GetDataStructure(AbstractSyntax):
     file: str
         The file path where the data is.
     tab: str
-        The sheetname where the data is.
+        Tab name from which the data is read. If file type is not a
+        spreadsheet this will be used as a separator.
     time_row_or_col: str
         The pointer to the cell or cellrange name that defines the
         interpolation time series data.
@@ -616,7 +618,8 @@ class GetConstantsStructure(AbstractSyntax):
     file: str
         The file path where the data is.
     tab: str
-        The sheetname where the data is.
+        Tab name from which the data is read. If file type is not a
+        spreadsheet this will be used as a separator.
     cell: str
         The pointer to the cell or the cellrange name that defines the data.
 
diff --git a/tests/pytest_pysd/pytest_serialize_externals.py b/tests/pytest_pysd/pytest_serialize_externals.py
index 33f45d77..639ae6aa 100644
--- a/tests/pytest_pysd/pytest_serialize_externals.py
+++ b/tests/pytest_pysd/pytest_serialize_externals.py
@@ -50,7 +50,7 @@ def test_serialize_externals_file_content(self, tmp_path, model):
         assert "description" in ds.attrs.keys()
         assert all(map(
             lambda x: x in ds.data_vars["_ext_data_data_forward"].attrs.keys(),
-            ["Py Name", "sheets", "files"]))
+            ["Py Name", "tabs", "files"]))
 
     @pytest.mark.parametrize(
         "model_path,include,exclude",