diff --git a/src/language/semantics/expression.ts b/src/language/semantics/expression.ts
index 69b7e86..83b7755 100644
--- a/src/language/semantics/expression.ts
+++ b/src/language/semantics/expression.ts
@@ -14,7 +14,7 @@ export const isExpression = (
   /^@[^@]/.test(node['0']) &&
   (!('1' in node) || typeof node[1] === 'object' || typeof node[1] === 'string')
 
-export const isExpressionWithArgument = <Keyword extends `@${string}`>(
+export const isKeywordExpressionWithArgument = <Keyword extends `@${string}`>(
   keyword: Keyword,
   node: Molecule | SemanticGraph,
 ): node is {
diff --git a/src/language/semantics/expressions/apply-expression.ts b/src/language/semantics/expressions/apply-expression.ts
index b4b5f4a..74778c2 100644
--- a/src/language/semantics/expressions/apply-expression.ts
+++ b/src/language/semantics/expressions/apply-expression.ts
@@ -1,7 +1,7 @@
 import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Molecule } from '../../parsing.js'
-import { isExpressionWithArgument } from '../expression.js'
+import { isKeywordExpressionWithArgument } from '../expression.js'
 import { makeObjectNode, type ObjectNode } from '../object-node.js'
 import { type SemanticGraph } from '../semantic-graph.js'
 import { readArgumentsFromExpression } from './expression-utilities.js'
@@ -17,7 +17,7 @@ export type ApplyExpression = ObjectNode & {
 export const readApplyExpression = (
   node: SemanticGraph | Molecule,
 ): Either<ElaborationError, ApplyExpression> =>
-  isExpressionWithArgument('@apply', node)
+  isKeywordExpressionWithArgument('@apply', node)
     ? either.map(
         readArgumentsFromExpression(node, ['function', 'argument']),
         ([f, argument]) => makeApplyExpression({ function: f, argument }),
diff --git a/src/language/semantics/expressions/check-expression.ts b/src/language/semantics/expressions/check-expression.ts
index 51f91bb..e44fcf2 100644
--- a/src/language/semantics/expressions/check-expression.ts
+++ b/src/language/semantics/expressions/check-expression.ts
@@ -1,7 +1,7 @@
 import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Molecule } from '../../parsing.js'
-import { isExpressionWithArgument } from '../expression.js'
+import { isKeywordExpressionWithArgument } from '../expression.js'
 import { makeObjectNode, type ObjectNode } from '../object-node.js'
 import { type SemanticGraph } from '../semantic-graph.js'
 import { readArgumentsFromExpression } from './expression-utilities.js'
@@ -17,7 +17,7 @@ export type CheckExpression = ObjectNode & {
 export const readCheckExpression = (
   node: SemanticGraph | Molecule,
 ): Either<ElaborationError, CheckExpression> =>
-  isExpressionWithArgument('@check', node)
+  isKeywordExpressionWithArgument('@check', node)
     ? either.map(
         readArgumentsFromExpression(node, ['value', 'type']),
         ([value, type]) => makeCheckExpression({ value, type }),
diff --git a/src/language/semantics/expressions/function-expression.ts b/src/language/semantics/expressions/function-expression.ts
index 49506c9..2cdd55f 100644
--- a/src/language/semantics/expressions/function-expression.ts
+++ b/src/language/semantics/expressions/function-expression.ts
@@ -1,7 +1,7 @@
 import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Atom, Molecule } from '../../parsing.js'
-import { isExpressionWithArgument } from '../expression.js'
+import { isKeywordExpressionWithArgument } from '../expression.js'
 import { makeObjectNode, type ObjectNode } from '../object-node.js'
 import { serialize, type SemanticGraph } from '../semantic-graph.js'
 import {
@@ -20,7 +20,7 @@ export type FunctionExpression = ObjectNode & {
 export const readFunctionExpression = (
   node: SemanticGraph | Molecule,
 ): Either<ElaborationError, FunctionExpression> =>
-  isExpressionWithArgument('@function', node)
+  isKeywordExpressionWithArgument('@function', node)
     ? either.flatMap(
         readArgumentsFromExpression(node, ['parameter', 'body']),
         ([parameter, body]): Either<ElaborationError, FunctionExpression> =>
diff --git a/src/language/semantics/expressions/if-expression.ts b/src/language/semantics/expressions/if-expression.ts
index 04072b1..4ce9ad8 100644
--- a/src/language/semantics/expressions/if-expression.ts
+++ b/src/language/semantics/expressions/if-expression.ts
@@ -1,7 +1,7 @@
 import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Molecule } from '../../parsing.js'
-import { isExpressionWithArgument } from '../expression.js'
+import { isKeywordExpressionWithArgument } from '../expression.js'
 import { makeObjectNode, type ObjectNode } from '../object-node.js'
 import { type SemanticGraph } from '../semantic-graph.js'
 import { readArgumentsFromExpression } from './expression-utilities.js'
@@ -19,7 +19,7 @@ export type IfExpression = ObjectNode & {
 export const readIfExpression = (
   node: SemanticGraph | Molecule,
 ): Either<ElaborationError, IfExpression> =>
-  isExpressionWithArgument('@if', node)
+  isKeywordExpressionWithArgument('@if', node)
     ? either.map(
         readArgumentsFromExpression(node, ['condition', 'then', 'else']),
         ([condition, then, otherwise]) =>
diff --git a/src/language/semantics/expressions/index-expression.ts b/src/language/semantics/expressions/index-expression.ts
index 3d3ab13..f03fd68 100644
--- a/src/language/semantics/expressions/index-expression.ts
+++ b/src/language/semantics/expressions/index-expression.ts
@@ -1,7 +1,7 @@
 import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Molecule } from '../../parsing.js'
-import { isExpressionWithArgument } from '../expression.js'
+import { isKeywordExpressionWithArgument } from '../expression.js'
 import { keyPathFromObjectNodeOrMolecule } from '../key-path.js'
 import {
   isObjectNode,
@@ -25,7 +25,7 @@ export type IndexExpression = ObjectNode & {
 export const readIndexExpression = (
   node: SemanticGraph | Molecule,
 ): Either<ElaborationError, IndexExpression> =>
-  isExpressionWithArgument('@index', node)
+  isKeywordExpressionWithArgument('@index', node)
     ? either.flatMap(
         readArgumentsFromExpression(node, ['object', 'query']),
         ([o, q]) => {
diff --git a/src/language/semantics/expressions/lookup-expression.ts b/src/language/semantics/expressions/lookup-expression.ts
index 3988534..239f3f0 100644
--- a/src/language/semantics/expressions/lookup-expression.ts
+++ b/src/language/semantics/expressions/lookup-expression.ts
@@ -1,7 +1,7 @@
 import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Atom, Molecule } from '../../parsing.js'
-import { isExpressionWithArgument } from '../expression.js'
+import { isKeywordExpressionWithArgument } from '../expression.js'
 import { keyPathToMolecule, type NonEmptyKeyPath } from '../key-path.js'
 import { makeObjectNode, type ObjectNode } from '../object-node.js'
 import {
@@ -24,7 +24,7 @@ export type LookupExpression = ObjectNode & {
 export const readLookupExpression = (
   node: SemanticGraph | Molecule,
 ): Either<ElaborationError, LookupExpression> =>
-  isExpressionWithArgument('@lookup', node)
+  isKeywordExpressionWithArgument('@lookup', node)
     ? either.flatMap(readArgumentsFromExpression(node, ['key']), ([key]) => {
         if (typeof key !== 'string') {
           return either.makeLeft({
diff --git a/src/language/semantics/expressions/runtime-expression.ts b/src/language/semantics/expressions/runtime-expression.ts
index bfb0703..8c9b729 100644
--- a/src/language/semantics/expressions/runtime-expression.ts
+++ b/src/language/semantics/expressions/runtime-expression.ts
@@ -1,7 +1,7 @@
 import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Molecule } from '../../parsing.js'
-import { isExpressionWithArgument } from '../expression.js'
+import { isKeywordExpressionWithArgument } from '../expression.js'
 import { isFunctionNode } from '../function-node.js'
 import { makeObjectNode, type ObjectNode } from '../object-node.js'
 import {
@@ -23,7 +23,7 @@ export type RuntimeExpression = ObjectNode & {
 export const readRuntimeExpression = (
   node: SemanticGraph | Molecule,
 ): Either<ElaborationError, RuntimeExpression> =>
-  isExpressionWithArgument('@runtime', node)
+  isKeywordExpressionWithArgument('@runtime', node)
     ? either.flatMap(readArgumentsFromExpression(node, ['function']), ([f]) => {
         const runtimeFunction = asSemanticGraph(f)
         if (