diff --git a/ctype.c b/ctype.c
index 151bb1c..c4bb557 100644
--- a/ctype.c
+++ b/ctype.c
@@ -13,7 +13,7 @@ bool is_space(char chr)
     return isspace(chr);
 }
 
-bool is_symbol_head(char chr)
+bool is_ident_head(char chr)
 {
     return isalpha(chr) ||
       chr == '!' ||
@@ -36,9 +36,9 @@ bool is_symbol_head(char chr)
       chr == '~';
 }
 
-bool is_symbol_tail(char chr)
+bool is_ident_tail(char chr)
 {
-    return is_symbol_head(chr) || isdigit(chr);
+    return is_ident_head(chr) || isdigit(chr);
 }
 
 bool is_number(char chr)
diff --git a/ctype.h b/ctype.h
index 0e3df0f..2d293ac 100644
--- a/ctype.h
+++ b/ctype.h
@@ -4,8 +4,8 @@
 #include <stdbool.h>
 
 bool is_space(char chr);
-bool is_symbol_head(char chr);
-bool is_symbol_tail(char chr);
+bool is_ident_head(char chr);
+bool is_ident_tail(char chr);
 bool is_number(char chr);
 
 #endif
diff --git a/enums.c b/enums.c
index 4fdd8b5..70615f3 100644
--- a/enums.c
+++ b/enums.c
@@ -14,7 +14,7 @@ const char *State_to_str(const enum State state)
     case STATE_SQUARE_CLOSE: return "STATE_SQUARE_CLOSE";
     case STATE_CURLY_OPEN:   return "STATE_CURLY_OPEN";
     case STATE_CURLY_CLOSE:  return "STATE_CURLY_CLOSE";
-    case STATE_SYMBOL:       return "STATE_SYMBOL";
+    case STATE_IDENT:        return "STATE_IDENT";
     case STATE_NUM:          return "STATE_NUM";
     }
     return NULL;
@@ -29,7 +29,7 @@ const char *TokenType_to_str(const enum TokenType token_type)
     case TOKEN_SQUARE_CLOSE: return "TOKEN_SQUARE_CLOSE";
     case TOKEN_CURLY_OPEN:   return "TOKEN_CURLY_OPEN";
     case TOKEN_CURLY_CLOSE:  return "TOKEN_CURLY_CLOSE";
-    case TOKEN_SYMBOL:       return "TOKEN_SYMBOL";
+    case TOKEN_IDENT:        return "TOKEN_IDENT";
     case TOKEN_NUM:          return "TOKEN_NUM";
     }
     return NULL;
@@ -56,7 +56,7 @@ State_to_token_type(const enum State state, enum TokenType *const token_type)
     case STATE_SQUARE_CLOSE: *token_type = TOKEN_SQUARE_CLOSE; break;
     case STATE_CURLY_OPEN:   *token_type = TOKEN_CURLY_OPEN;   break;
     case STATE_CURLY_CLOSE:  *token_type = TOKEN_CURLY_CLOSE;  break;
-    case STATE_SYMBOL:       *token_type = TOKEN_SYMBOL;       break;
+    case STATE_IDENT:        *token_type = TOKEN_IDENT;        break;
     case STATE_NUM:          *token_type = TOKEN_NUM;          break;
     default: return false;
     }
diff --git a/enums.h b/enums.h
index f3fc5cd..115374c 100644
--- a/enums.h
+++ b/enums.h
@@ -12,7 +12,7 @@ enum State {
     STATE_SQUARE_CLOSE,
     STATE_CURLY_OPEN,
     STATE_CURLY_CLOSE,
-    STATE_SYMBOL,
+    STATE_IDENT,
     STATE_NUM,
 };
 
@@ -23,7 +23,7 @@ enum TokenType {
     TOKEN_SQUARE_CLOSE,
     TOKEN_CURLY_OPEN,
     TOKEN_CURLY_CLOSE,
-    TOKEN_SYMBOL,
+    TOKEN_IDENT,
     TOKEN_NUM,
 };
 
diff --git a/lexer.c b/lexer.c
index 50a1808..a0a0c29 100644
--- a/lexer.c
+++ b/lexer.c
@@ -62,8 +62,8 @@ void lex(const char chr)
         } else if (is_space(chr)) {
             state = STATE_WHITESPACE;
             buffer_add(chr);
-        } else if (is_symbol_head(chr)) {
-            state = STATE_SYMBOL;
+        } else if (is_ident_head(chr)) {
+            state = STATE_IDENT;
             buffer_add(chr);
         } else if (is_number(chr)) {
             state = STATE_NUM;
@@ -105,10 +105,10 @@ void lex(const char chr)
             buffer_add(chr);
         } else if (is_space(chr)) {
             buffer_add(chr);
-        } else if (is_symbol_head(chr)) {
+        } else if (is_ident_head(chr)) {
             token_add(state, buffer);
             buffer_clean();
-            state = STATE_SYMBOL;
+            state = STATE_IDENT;
             buffer[buffer_index++] = chr;
         } else if (is_number(chr)) {
             token_add(state, buffer);
@@ -160,10 +160,10 @@ void lex(const char chr)
             buffer_clean();
             state = STATE_WHITESPACE;
             buffer_add(chr);
-        } else if (is_symbol_head(chr)) {
+        } else if (is_ident_head(chr)) {
             token_add(state, buffer);
             buffer_clean();
-            state = STATE_SYMBOL;
+            state = STATE_IDENT;
             buffer_add(chr);
         } else if (is_number(chr)) {
             token_add(state, buffer);
@@ -174,7 +174,7 @@ void lex(const char chr)
             abort();
         }
         break;
-    case STATE_SYMBOL:
+    case STATE_IDENT:
         if (chr == '(') {
             token_add(state, buffer);
             buffer_clean();
@@ -210,7 +210,7 @@ void lex(const char chr)
             buffer_clean();
             state = STATE_WHITESPACE;
             buffer_add(chr);
-        } else if (is_symbol_tail(chr)) {
+        } else if (is_ident_tail(chr)) {
             buffer_add(chr);
         } else {
             abort();
diff --git a/parser.c b/parser.c
index e517a80..1d2f7c1 100644
--- a/parser.c
+++ b/parser.c
@@ -33,7 +33,7 @@ struct Object *expr()
     case TOKEN_SQUARE_OPEN:
     case TOKEN_CURLY_OPEN:
         return parens();
-    case TOKEN_SYMBOL:
+    case TOKEN_IDENT:
     {
         struct Object *const object = Object_new_symbol(tokens_top()->val);
         tokens_pop();