diff --git a/README.md b/README.md
index e63a814..c572264 100644
--- a/README.md
+++ b/README.md
@@ -422,7 +422,7 @@ program.add_argument("--input_files")
 ```
 ```cpp
 program.add_argument("--input_files")
-  .nargs(argparse::nargs_pattern::zero_or_one);  // "?" in Python. This accepts an argument optionally.
+  .nargs(argparse::nargs_pattern::optional);  // "?" in Python. This accepts an argument optionally.
 ```
 
 ### Compound Arguments
diff --git a/include/argparse/argparse.hpp b/include/argparse/argparse.hpp
index c5ad384..7e8f35a 100644
--- a/include/argparse/argparse.hpp
+++ b/include/argparse/argparse.hpp
@@ -360,7 +360,7 @@ public:
 };
 
 enum class nargs_pattern {
-  zero_or_one,
+  optional,
   any,
   at_least_one
 };
@@ -507,7 +507,7 @@ public:
 
   Argument &nargs(nargs_pattern pattern) {
     switch (pattern) {
-    case nargs_pattern::zero_or_one:
+    case nargs_pattern::optional:
       m_num_args_range = SizeRange{0, 1};
       break;
     case nargs_pattern::any: