diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4ae7d26..e10efcb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,10 @@ All notable changes to this project will be documented in this file.
   * Fix `RFC3987_SYNTAX_TERMS` correctly containing "ipath_rootless" (via [#41])
   * Fix `RFC3987_SYNTAX_TERMS` correctly containing "ipath_empty" (via [#41])
   * Fix `ucschar` range (via [#45])
+  * Fix `parse()`'s typehint for arg `term` (via [#50])  
+    Narrowed down to valid values: "iri", "iri_reference", "absolute_iri"
+  * Fix `is_valid_syntax`'s typehint for arg `term` (via [#50])  
+    Narrowed down to valid values: "iri", "iri_reference", "absolute_iri"
 * Added
   * Function `is_valid_syntax_scheme` (via [#48])
   * Function `is_valid_syntax_non_zero` (via [#48])
@@ -28,6 +32,7 @@ All notable changes to this project will be documented in this file.
 [#45]: https://github.com/jkowalleck/rfc3987-syntax2/pull/45
 [#48]: https://github.com/jkowalleck/rfc3987-syntax2/pull/48
 [#49]: https://github.com/jkowalleck/rfc3987-syntax2/pull/49
+[#50]: https://github.com/jkowalleck/rfc3987-syntax2/pull/50
 
 ## v1.2.0 - 2026-07-16
 
diff --git a/src/rfc3987_syntax2/syntax_helpers.py b/src/rfc3987_syntax2/syntax_helpers.py
index 8592598..dc51199 100644
--- a/src/rfc3987_syntax2/syntax_helpers.py
+++ b/src/rfc3987_syntax2/syntax_helpers.py
@@ -4,7 +4,7 @@
 
 from pathlib import Path
 from threading import Lock
-from typing import Any, Callable, Optional, TYPE_CHECKING
+from typing import Any, Callable, Optional, TYPE_CHECKING, Literal
 
 from lark import Lark, ParseTree, exceptions
 
@@ -110,11 +110,14 @@
     "pct_encoded",
 ]
 
-def parse(term: str, value: str) -> 'ParseTree':
+_SYNTAX_PARSER_STARTS = ["iri", "iri_reference", "absolute_iri"]
+_SYNTAX_PARSER_TERM = Literal["iri", "iri_reference", "absolute_iri"]
+
+def parse(term: _SYNTAX_PARSER_TERM, value: str) -> 'ParseTree':
     return _get_syntax_parser().parse(value, start=term)
 
 
-def is_valid_syntax(term: str, value: str) -> bool:
+def is_valid_syntax(term: _SYNTAX_PARSER_TERM, value: str) -> bool:
     try:
         parse(term=term, value=value)
         return True
@@ -167,7 +170,7 @@ def _get_syntax_parser() -> Lark:
     with _syntax_parser_lock:
         if _syntax_parser is None:
             _syntax_parser = Lark(grammar,
-                                  start=["iri", "iri_reference", "absolute_iri"],
+                                  start=_SYNTAX_PARSER_STARTS,
                                   parser=RFC3987_SYNTAX_PARSER_TYPE)
         return _syntax_parser