diff --git a/crates/frontend/src/ast.rs b/crates/frontend/src/ast.rs
index 4881bad..62b2d4c 100644
--- a/crates/frontend/src/ast.rs
+++ b/crates/frontend/src/ast.rs
@@ -23,8 +23,6 @@ use strum::{EnumDiscriminants, EnumIter};
 
 use crate::prelude::*;
 
-// TODO: rename all `atom` references to `apply`
-
 /// Retrieves, but does not parse, all top-level items in a file.
 // TODO: is `Vec` the most efficient to incrementally update here?
 #[salsa::tracked]
@@ -231,7 +229,7 @@ pub fn expr(db: &dyn Database, ast: AstNode) -> Expr {
     } else if let Some(var) = ast.get_field(db, "variable") {
         let name = var.contents(db).to_string();
         Extra(Arc::new(ExprExtra::VariableName(name)))
-    } else if let Some(ast) = ast.get_field(db, "atom") {
+    } else if let Some(ast) = ast.get_field(db, "apply") {
         Extra(Arc::new(ExprExtra::Apply(apply(db, ast))))
     } else if let Some(tuple) = ast.get_field(db, "tuple") {
         let els = tuple.get_fields(db, "el").map(|el| expr(db, el)).collect();
@@ -280,7 +278,7 @@ pub fn aggregate(db: &dyn Database, ast: AstNode) -> Aggregate {
         .map(|ast| ast.with_contents(db))
         .collect();
 
-    let body = if let Some(ast) = ast.get_field(db, "atom") {
+    let body = if let Some(ast) = ast.get_field(db, "apply") {
         AggregateBody::Apply(apply(db, ast))
     } else {
         let clauses = ast.get_fields(db, "clause").map(|ast| expr(db, ast));
diff --git a/tree-sitter-kerolox/grammar.js b/tree-sitter-kerolox/grammar.js
index b850c1c..1318f0a 100644
--- a/tree-sitter-kerolox/grammar.js
+++ b/tree-sitter-kerolox/grammar.js
@@ -112,7 +112,7 @@ export default grammar({
       field("variable", $.variable),
 
       // composites
-      field("atom", $.atom),
+      field("apply", $.apply),
       field("tuple", $.tuple),
       field("aggregate", $.aggregate),
 
@@ -130,8 +130,7 @@ export default grammar({
       seq('(', field("parens", $.expr), ')'),
     ),
 
-    // TODO: rename to "apply"
-    atom: $ => prec.right(2, seq(field("head", $.symbol), field("body", $.expr))),
+    apply: $ => prec.right(2, seq(field("head", $.symbol), field("body", $.expr))),
 
     tuple: $ => parenListComma(field("el", $.expr)),
 
@@ -139,7 +138,7 @@ export default grammar({
       field("op", $.aggregate_op),
       optional(seq(list(field("witness", $.variable)), ":")),
       choice(
-        field("atom", $.atom),
+        field("apply", $.apply),
         seq("{", field("body", $.rule_body ), "}"),
       ),
     ),
diff --git a/tree-sitter-kerolox/queries/highlights.scm b/tree-sitter-kerolox/queries/highlights.scm
index 82394d3..5f7705a 100644
--- a/tree-sitter-kerolox/queries/highlights.scm
+++ b/tree-sitter-kerolox/queries/highlights.scm
@@ -10,7 +10,7 @@
 
 (rule relation: (symbol) @constructor)
 (definition relation: (symbol) @function)
-(atom head: (symbol) @function)
+(apply head: _ @function)
 
 [ ":-" "," "." ":" ] @punctuation.delimiter
 [ "(" ")" "{" "}" ] @punctuation.bracket
diff --git a/tree-sitter-kerolox/src/grammar.json b/tree-sitter-kerolox/src/grammar.json
index 5ed75f1..379fd1e 100644
--- a/tree-sitter-kerolox/src/grammar.json
+++ b/tree-sitter-kerolox/src/grammar.json
@@ -545,10 +545,10 @@
         },
         {
           "type": "FIELD",
-          "name": "atom",
+          "name": "apply",
           "content": {
             "type": "SYMBOL",
-            "name": "atom"
+            "name": "apply"
           }
         },
         {
@@ -638,7 +638,7 @@
         }
       ]
     },
-    "atom": {
+    "apply": {
       "type": "PREC_RIGHT",
       "value": 2,
       "content": {
@@ -784,10 +784,10 @@
           "members": [
             {
               "type": "FIELD",
-              "name": "atom",
+              "name": "apply",
               "content": {
                 "type": "SYMBOL",
-                "name": "atom"
+                "name": "apply"
               }
             },
             {
diff --git a/tree-sitter-kerolox/src/node-types.json b/tree-sitter-kerolox/src/node-types.json
index ea603b2..3da8ffd 100644
--- a/tree-sitter-kerolox/src/node-types.json
+++ b/tree-sitter-kerolox/src/node-types.json
@@ -3,12 +3,12 @@
     "type": "aggregate",
     "named": true,
     "fields": {
-      "atom": {
+      "apply": {
         "multiple": false,
         "required": false,
         "types": [
           {
-            "type": "atom",
+            "type": "apply",
             "named": true
           }
         ]
@@ -45,6 +45,32 @@
       }
     }
   },
+  {
+    "type": "apply",
+    "named": true,
+    "fields": {
+      "body": {
+        "multiple": false,
+        "required": true,
+        "types": [
+          {
+            "type": "expr",
+            "named": true
+          }
+        ]
+      },
+      "head": {
+        "multiple": false,
+        "required": true,
+        "types": [
+          {
+            "type": "symbol",
+            "named": true
+          }
+        ]
+      }
+    }
+  },
   {
     "type": "assumption",
     "named": true,
@@ -71,32 +97,6 @@
       }
     }
   },
-  {
-    "type": "atom",
-    "named": true,
-    "fields": {
-      "body": {
-        "multiple": false,
-        "required": true,
-        "types": [
-          {
-            "type": "expr",
-            "named": true
-          }
-        ]
-      },
-      "head": {
-        "multiple": false,
-        "required": true,
-        "types": [
-          {
-            "type": "symbol",
-            "named": true
-          }
-        ]
-      }
-    }
-  },
   {
     "type": "binary_expr",
     "named": true,
@@ -267,12 +267,12 @@
           }
         ]
       },
-      "atom": {
+      "apply": {
         "multiple": false,
         "required": false,
         "types": [
           {
-            "type": "atom",
+            "type": "apply",
             "named": true
           }
         ]
diff --git a/tree-sitter-kerolox/src/parser.c b/tree-sitter-kerolox/src/parser.c
index 8f35598..1faee5b 100644
--- a/tree-sitter-kerolox/src/parser.c
+++ b/tree-sitter-kerolox/src/parser.c
@@ -72,7 +72,7 @@ enum ts_symbol_identifiers {
   sym_assumption = 50,
   sym_rule_body = 51,
   sym_expr = 52,
-  sym_atom = 53,
+  sym_apply = 53,
   sym_tuple = 54,
   sym_aggregate = 55,
   sym_unary_expr = 56,
@@ -141,7 +141,7 @@ static const char * const ts_symbol_names[] = {
   [sym_assumption] = "assumption",
   [sym_rule_body] = "rule_body",
   [sym_expr] = "expr",
-  [sym_atom] = "atom",
+  [sym_apply] = "apply",
   [sym_tuple] = "tuple",
   [sym_aggregate] = "aggregate",
   [sym_unary_expr] = "unary_expr",
@@ -210,7 +210,7 @@ static const TSSymbol ts_symbol_map[] = {
   [sym_assumption] = sym_assumption,
   [sym_rule_body] = sym_rule_body,
   [sym_expr] = sym_expr,
-  [sym_atom] = sym_atom,
+  [sym_apply] = sym_apply,
   [sym_tuple] = sym_tuple,
   [sym_aggregate] = sym_aggregate,
   [sym_unary_expr] = sym_unary_expr,
@@ -438,7 +438,7 @@ static const TSSymbolMetadata ts_symbol_metadata[] = {
     .visible = true,
     .named = true,
   },
-  [sym_atom] = {
+  [sym_apply] = {
     .visible = true,
     .named = true,
   },
@@ -494,7 +494,7 @@ static const TSSymbolMetadata ts_symbol_metadata[] = {
 
 enum ts_field_identifiers {
   field_aggregate = 1,
-  field_atom = 2,
+  field_apply = 2,
   field_binary = 3,
   field_body = 4,
   field_clause = 5,
@@ -530,7 +530,7 @@ enum ts_field_identifiers {
 static const char * const ts_field_names[] = {
   [0] = NULL,
   [field_aggregate] = "aggregate",
-  [field_atom] = "atom",
+  [field_apply] = "apply",
   [field_binary] = "binary",
   [field_body] = "body",
   [field_clause] = "clause",
@@ -639,7 +639,7 @@ static const TSFieldMapEntry ts_field_map_entries[] = {
   [5] =
     {field_integer, 0},
   [6] =
-    {field_atom, 0},
+    {field_apply, 0},
   [7] =
     {field_tuple, 0},
   [8] =
@@ -654,7 +654,7 @@ static const TSFieldMapEntry ts_field_map_entries[] = {
     {field_body, 1},
     {field_head, 0},
   [14] =
-    {field_atom, 1},
+    {field_apply, 1},
     {field_op, 0},
   [16] =
     {field_head, 1},
@@ -721,7 +721,7 @@ static const TSFieldMapEntry ts_field_map_entries[] = {
   [57] =
     {field_witness, 1},
   [58] =
-    {field_atom, 3},
+    {field_apply, 3},
     {field_op, 0},
     {field_witness, 1},
   [61] =
@@ -754,7 +754,7 @@ static const TSFieldMapEntry ts_field_map_entries[] = {
     {field_relation, 3},
     {field_type, 4},
   [83] =
-    {field_atom, 4},
+    {field_apply, 4},
     {field_op, 0},
     {field_witness, 1},
     {field_witness, 2, .inherited = true},
@@ -1711,7 +1711,7 @@ static const uint16_t ts_parse_table[LARGE_STATE_COUNT][SYMBOL_COUNT] = {
     [sym_comment] = STATE(2),
     [sym_integer] = STATE(46),
     [sym_expr] = STATE(37),
-    [sym_atom] = STATE(28),
+    [sym_apply] = STATE(28),
     [sym_tuple] = STATE(30),
     [sym_aggregate] = STATE(24),
     [sym_unary_expr] = STATE(27),
@@ -1783,7 +1783,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -1829,7 +1829,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -1877,7 +1877,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -1921,7 +1921,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -1967,7 +1967,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2013,7 +2013,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2059,7 +2059,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2105,7 +2105,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2151,7 +2151,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2195,7 +2195,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2235,7 +2235,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2282,7 +2282,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2326,7 +2326,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2372,7 +2372,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2414,7 +2414,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2458,7 +2458,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2502,7 +2502,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2546,7 +2546,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2590,7 +2590,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -2634,7 +2634,7 @@ static const uint16_t ts_small_parse_table[] = {
     STATE(27), 1,
       sym_unary_expr,
     STATE(28), 1,
-      sym_atom,
+      sym_apply,
     STATE(29), 1,
       sym_binary_expr,
     STATE(30), 1,
@@ -4074,7 +4074,7 @@ static const uint16_t ts_small_parse_table[] = {
     ACTIONS(276), 1,
       anon_sym_LBRACE,
     STATE(26), 1,
-      sym_atom,
+      sym_apply,
     STATE(84), 1,
       sym_comment,
   [3084] = 6,
@@ -4237,7 +4237,7 @@ static const uint16_t ts_small_parse_table[] = {
     ACTIONS(313), 1,
       anon_sym_LBRACE,
     STATE(41), 1,
-      sym_atom,
+      sym_apply,
     STATE(96), 1,
       sym_comment,
   [3321] = 6,
@@ -4428,7 +4428,7 @@ static const uint16_t ts_small_parse_table[] = {
     ACTIONS(346), 1,
       anon_sym_LBRACE,
     STATE(45), 1,
-      sym_atom,
+      sym_apply,
     STATE(111), 1,
       sym_comment,
   [3598] = 6,
@@ -5145,8 +5145,8 @@ static const TSParseActionEntry ts_parse_actions[] = {
   [103] = {.entry = {.count = 1, .reusable = false}}, REDUCE(sym_expr, 3, 0, 21),
   [105] = {.entry = {.count = 1, .reusable = true}}, SHIFT(16),
   [107] = {.entry = {.count = 1, .reusable = false}}, SHIFT(16),
-  [109] = {.entry = {.count = 1, .reusable = true}}, REDUCE(sym_atom, 2, 0, 13),
-  [111] = {.entry = {.count = 1, .reusable = false}}, REDUCE(sym_atom, 2, 0, 13),
+  [109] = {.entry = {.count = 1, .reusable = true}}, REDUCE(sym_apply, 2, 0, 13),
+  [111] = {.entry = {.count = 1, .reusable = false}}, REDUCE(sym_apply, 2, 0, 13),
   [113] = {.entry = {.count = 1, .reusable = true}}, REDUCE(sym_tuple, 4, 0, 33),
   [115] = {.entry = {.count = 1, .reusable = false}}, REDUCE(sym_tuple, 4, 0, 33),
   [117] = {.entry = {.count = 1, .reusable = true}}, REDUCE(sym_tuple, 4, 0, 34),