diff --git a/include/arl/parser/ast.h b/include/arl/parser/ast.h
index b4565c8..a33ceee 100644
--- a/include/arl/parser/ast.h
+++ b/include/arl/parser/ast.h
@@ -15,23 +15,23 @@
 /// Types the AST can encode
 typedef enum
 {
-  AST_NODE_TYPE_PRIMITIVE = 0,
+  AST_NODE_TYPE_KNOWN = 0,
   AST_NODE_TYPE_SYMBOL,
   AST_NODE_TYPE_STRING,
 
   NUM_AST_NODE_TYPES,
 } ast_node_type_t;
 
-/// Primitives (values, callables, etc) as symbols
+/// Known symbols - may reference callables or values.
 typedef enum
 {
-  AST_PRIM_NIL = 0,
-  AST_PRIM_PUTSTR,
+  AST_KNOWN_NIL = 0,
+  AST_KNOWN_PUTSTR,
 
-  NUM_AST_PRIMS,
-} ast_prim_t;
+  NUM_AST_KNOWNS,
+} ast_known_t;
 
-const char *ast_prim_to_cstr(ast_prim_t);
+const char *ast_known_to_cstr(ast_known_t);
 
 /// Node of the AST as a tagged union
 typedef struct
@@ -40,13 +40,13 @@ typedef struct
   ast_node_type_t type;
   union
   {
-    ast_prim_t as_prim;
+    ast_known_t as_known;
     sv_t as_symbol;
     sv_t as_string;
   } value;
 } ast_node_t;
 
-ast_node_t ast_node_prim(u64 byte, ast_prim_t primitive);
+ast_node_t ast_node_known(u64 byte, ast_known_t known);
 ast_node_t ast_node_symbol(u64 byte, sv_t symbol);
 ast_node_t ast_node_string(u64 byte, sv_t string);
 void ast_node_print(FILE *fp, ast_node_t *node);
diff --git a/src/parser/ast.c b/src/parser/ast.c
index a50fc00..f7a4772 100644
--- a/src/parser/ast.c
+++ b/src/parser/ast.c
@@ -9,25 +9,25 @@
 #include <arl/lib/vec.h>
 #include <arl/parser/ast.h>
 
-const char *ast_prim_to_cstr(ast_prim_t prim)
+const char *ast_known_to_cstr(ast_known_t known)
 {
-  switch (prim)
+  switch (known)
   {
-  case AST_PRIM_NIL:
+  case AST_KNOWN_NIL:
     return "nil";
-  case AST_PRIM_PUTSTR:
+  case AST_KNOWN_PUTSTR:
     return "putstr";
   default:
-    FAIL("Unexpected AST primitive value: %d\n", prim);
+    FAIL("Unexpected AST_KNOWN value: %d\n", known);
   }
 }
 
-ast_node_t ast_node_prim(u64 byte, ast_prim_t primitive)
+ast_node_t ast_node_known(u64 byte, ast_known_t known)
 {
   return (ast_node_t){
       .byte_location = byte,
-      .type          = AST_NODE_TYPE_PRIMITIVE,
-      .value         = {.as_prim = primitive},
+      .type          = AST_NODE_TYPE_KNOWN,
+      .value         = {.as_known = known},
   };
 }
 
@@ -58,8 +58,8 @@ void ast_node_print(FILE *fp, ast_node_t *node)
   }
   switch (node->type)
   {
-  case AST_NODE_TYPE_PRIMITIVE:
-    fprintf(fp, "PRIMITIVE(%s)", ast_prim_to_cstr(node->value.as_prim));
+  case AST_NODE_TYPE_KNOWN:
+    fprintf(fp, "KNOWN(%s)", ast_known_to_cstr(node->value.as_known));
     break;
   case AST_NODE_TYPE_SYMBOL:
     fprintf(fp, "SYMBOL(" PR_SV ")", SV_FMT(node->value.as_symbol));
diff --git a/src/parser/parser.c b/src/parser/parser.c
index 8fb3f9b..808f805 100644
--- a/src/parser/parser.c
+++ b/src/parser/parser.c
@@ -123,16 +123,16 @@ parse_err_t parse_symbol(parse_stream_t *stream, ast_node_t *ret)
   sv_t symbol =
       SV(current_contents.data, sv_while(current_contents, SYMBOL_CHARS));
 
-  // see if symbol is one of the AST primitives we can parse AOT
-  static_assert(NUM_AST_PRIMS == 2, "Expected number of AST primitives");
-  for (ast_prim_t i = 0; i < NUM_AST_PRIMS; ++i)
+  // see if symbol is one of the already known symbols
+  static_assert(NUM_AST_KNOWNS == 2, "Expected number of AST KNOWN");
+  for (ast_known_t i = 0; i < NUM_AST_KNOWNS; ++i)
   {
-    const char *possible_prim = ast_prim_to_cstr(i);
+    const char *possible_prim = ast_known_to_cstr(i);
     if (strlen(possible_prim) == symbol.size &&
         strncmp(possible_prim, symbol.data, symbol.size) == 0)
     {
-      // Found a matching primitive
-      *ret = ast_node_prim(stream->byte, i);
+      // Found a matching known symbol
+      *ret = ast_node_known(stream->byte, i);
       goto end;
     }
   }