diff --git a/tests/utils/test_parser.py b/tests/utils/test_parser.py
index 6998cca..50179c7 100644
--- a/tests/utils/test_parser.py
+++ b/tests/utils/test_parser.py
@@ -17,8 +17,8 @@ def parser() -> Generator[Parser, None, None]:
     yield parser
 
 
-def test_parse_variables(parser: Parser):
-    assert parser.variables == {
+def test_parse_sub_pairs(parser: Parser):
+    assert parser.sub_pairs == {
         'varst': 'variable to reStructuredText',
         'version': '0.2.0',
         'release': 'v0.2.0',
diff --git a/varst/application.py b/varst/application.py
index 84226ff..8e3c312 100644
--- a/varst/application.py
+++ b/varst/application.py
@@ -24,6 +24,6 @@ def run(self, argv: Optional[Sequence[str]]) -> None:
 
         rst_file = RstFile(src=self.parser.input_file)
         substitution = Substitution(rst_file)
-        for k, v in self.parser.variables.items():
+        for k, v in self.parser.sub_pairs.items():
             substitution.update(k, v)
         rst_file.save(dest=self.parser.output_file)
diff --git a/varst/utils/parser.py b/varst/utils/parser.py
index 1ecffb1..f10d96d 100644
--- a/varst/utils/parser.py
+++ b/varst/utils/parser.py
@@ -17,7 +17,7 @@ class Parser:
 
     input_file: str = ""
     output_file: str = ""
-    variables: Dict[str, str] = {}
+    sub_pairs: Dict[str, str] = {}
 
     def __init__(self) -> None:
         self._parser.add_argument(
@@ -53,7 +53,7 @@ def parse(self, argv: Optional[Sequence[str]]) -> None:
         self.input_file = self.output_file = arg_dict['input']
         if arg_dict['output'] is not None:
             self.output_file = arg_dict['output']
-        self.variables = _parse_kv(arg_dict['name=value'])
+        self.sub_pairs = _parse_kv(arg_dict['name=value'])
 
 
 _VARIABLE_PATTERN = re.compile(r"[^=]+=[^=]+")