diff --git a/toolchain/check/check.cpp b/toolchain/check/check.cpp
index 5e39e00d5213..f312b784f1b5 100644
--- a/toolchain/check/check.cpp
+++ b/toolchain/check/check.cpp
@@ -400,10 +400,10 @@ static auto MaybeDumpCppAST(llvm::ArrayRef<Unit> units,
   }
 
   for (const Unit& unit : units) {
-    if (!unit.cpp_ast || !*unit.cpp_ast) {
+    if (!unit.clang_ast_unit || !*unit.clang_ast_unit) {
       continue;
     }
-    clang::ASTContext& ast_context = (*unit.cpp_ast)->getASTContext();
+    clang::ASTContext& ast_context = (*unit.clang_ast_unit)->getASTContext();
     ast_context.getTranslationUnitDecl()->dump(*options.dump_cpp_ast_stream);
   }
 }
diff --git a/toolchain/check/check.h b/toolchain/check/check.h
index 952635b9355f..5eeb270414ad 100644
--- a/toolchain/check/check.h
+++ b/toolchain/check/check.h
@@ -30,7 +30,7 @@ struct Unit {
 
   // Storage for the unit's Clang AST. The unique_ptr should start empty, and
   // can be assigned as part of checking.
-  std::unique_ptr<clang::ASTUnit>* cpp_ast;
+  std::unique_ptr<clang::ASTUnit>* clang_ast_unit;
 };
 
 struct CheckParseTreesOptions {
diff --git a/toolchain/check/check_unit.cpp b/toolchain/check/check_unit.cpp
index d1ede66d5a3d..05314e6b7054 100644
--- a/toolchain/check/check_unit.cpp
+++ b/toolchain/check/check_unit.cpp
@@ -154,10 +154,11 @@ auto CheckUnit::InitPackageScopeAndImports() -> void {
 
   const auto& cpp_imports = unit_and_imports_->cpp_imports;
   if (!cpp_imports.empty()) {
-    auto* cpp_ast = unit_and_imports_->unit->cpp_ast;
-    CARBON_CHECK(cpp_ast);
-    CARBON_CHECK(!cpp_ast->get());
-    *cpp_ast = ImportCppFiles(context_, cpp_imports, fs_, clang_invocation_);
+    auto* clang_ast_unit = unit_and_imports_->unit->clang_ast_unit;
+    CARBON_CHECK(clang_ast_unit);
+    CARBON_CHECK(!clang_ast_unit->get());
+    *clang_ast_unit =
+        ImportCppFiles(context_, cpp_imports, fs_, clang_invocation_);
   }
 }
 
diff --git a/toolchain/check/context.h b/toolchain/check/context.h
index b44667645734..61bad0600d7a 100644
--- a/toolchain/check/context.h
+++ b/toolchain/check/context.h
@@ -269,7 +269,7 @@ class Context {
     return sem_ir().import_ir_insts();
   }
   auto ast_context() -> clang::ASTContext& {
-    return sem_ir().cpp_ast()->getASTContext();
+    return sem_ir().clang_ast_unit()->getASTContext();
   }
   auto names() -> SemIR::NameStoreWrapper { return sem_ir().names(); }
   auto name_scopes() -> SemIR::NameScopeStore& {
diff --git a/toolchain/check/cpp_thunk.cpp b/toolchain/check/cpp_thunk.cpp
index dedef2a678ad..4265e6d5768a 100644
--- a/toolchain/check/cpp_thunk.cpp
+++ b/toolchain/check/cpp_thunk.cpp
@@ -290,7 +290,7 @@ auto BuildCppThunk(Context& context, const SemIR::Function& callee_function)
       context, *callee_function_decl, thunk_param_types);
 
   // Build the thunk function body.
-  clang::Sema& sema = context.sem_ir().cpp_ast()->getSema();
+  clang::Sema& sema = context.sem_ir().clang_ast_unit()->getSema();
   clang::Sema::ContextRAII context_raii(sema, thunk_function_decl);
   sema.ActOnStartOfFunctionDef(nullptr, thunk_function_decl);
 
diff --git a/toolchain/check/import_cpp.cpp b/toolchain/check/import_cpp.cpp
index 4e9def1f584b..8874e5075f62 100644
--- a/toolchain/check/import_cpp.cpp
+++ b/toolchain/check/import_cpp.cpp
@@ -230,7 +230,7 @@ class CarbonClangDiagnosticConsumer : public clang::DiagnosticConsumer {
   // Outputs Carbon diagnostics based on the collected Clang diagnostics. Must
   // be called after the AST is set in the context.
   auto EmitDiagnostics() -> void {
-    CARBON_CHECK(sem_ir_->cpp_ast(),
+    CARBON_CHECK(sem_ir_->clang_ast_unit(),
                  "Attempted to emit diagnostics before the AST Unit is loaded");
 
     for (size_t i = 0; i != diagnostic_infos_.size(); ++i) {
@@ -386,7 +386,7 @@ static auto GenerateAst(
   // Attach the AST to SemIR. This needs to be done before we can emit any
   // diagnostics, so their locations can be properly interpreted by our
   // diagnostics machinery.
-  context.sem_ir().set_cpp_ast(ast.get());
+  context.sem_ir().set_clang_ast_unit(ast.get());
 
   // Emit any diagnostics we queued up while building the AST.
   context.emitter().Flush();
@@ -431,7 +431,7 @@ auto ImportCppFiles(Context& context,
     return nullptr;
   }
 
-  CARBON_CHECK(!context.sem_ir().cpp_ast());
+  CARBON_CHECK(!context.sem_ir().clang_ast_unit());
 
   PackageNameId package_id = imports.front().package_id;
   CARBON_CHECK(
@@ -468,7 +468,7 @@ static auto ClangLookupName(Context& context, SemIR::NameScopeId scope_id,
     return std::nullopt;
   }
 
-  clang::ASTUnit* ast = context.sem_ir().cpp_ast();
+  clang::ASTUnit* ast = context.sem_ir().clang_ast_unit();
   CARBON_CHECK(ast);
   clang::Sema& sema = ast->getSema();
 
@@ -504,7 +504,7 @@ static auto ClangConstructorLookup(const Context& context,
     -> clang::DeclContextLookupResult {
   const SemIR::NameScope& scope = context.sem_ir().name_scopes().Get(scope_id);
 
-  clang::Sema& sema = context.sem_ir().cpp_ast()->getSema();
+  clang::Sema& sema = context.sem_ir().clang_ast_unit()->getSema();
   clang::Decl* decl =
       context.sem_ir().clang_decls().Get(scope.clang_decl_context_id()).decl;
   return sema.LookupConstructors(cast<clang::CXXRecordDecl>(decl));
@@ -531,7 +531,7 @@ static auto IsDeclInjectedClassName(const Context& context,
   const auto* scope_record_decl = cast<clang::CXXRecordDecl>(clang_decl.decl);
 
   const clang::ASTContext& ast_context =
-      context.sem_ir().cpp_ast()->getASTContext();
+      context.sem_ir().clang_ast_unit()->getASTContext();
   CARBON_CHECK(
       ast_context.getCanonicalType(
           ast_context.getRecordType(scope_record_decl)) ==
@@ -974,7 +974,7 @@ static auto BuildClassDefinition(Context& context,
 auto ImportCppClassDefinition(Context& context, SemIR::LocId loc_id,
                               SemIR::ClassId class_id,
                               SemIR::ClangDeclId clang_decl_id) -> bool {
-  clang::ASTUnit* ast = context.sem_ir().cpp_ast();
+  clang::ASTUnit* ast = context.sem_ir().clang_ast_unit();
   CARBON_CHECK(ast);
 
   auto* clang_decl = cast<clang::CXXRecordDecl>(
diff --git a/toolchain/driver/compile_subcommand.cpp b/toolchain/driver/compile_subcommand.cpp
index 20609541c3f9..f0414b49247d 100644
--- a/toolchain/driver/compile_subcommand.cpp
+++ b/toolchain/driver/compile_subcommand.cpp
@@ -532,7 +532,7 @@ class CompilationUnit {
   std::optional<std::function<auto()->const Parse::TreeAndSubtrees&>>
       tree_and_subtrees_getter_;
   std::optional<SemIR::File> sem_ir_;
-  std::unique_ptr<clang::ASTUnit> cpp_ast_;
+  std::unique_ptr<clang::ASTUnit> clang_ast_unit_;
   std::unique_ptr<llvm::LLVMContext> llvm_context_;
   std::unique_ptr<llvm::Module> module_;
 };
@@ -703,7 +703,7 @@ auto CompilationUnit::GetCheckUnit() -> Check::Unit {
           .value_stores = &value_stores_,
           .timings = timings_ ? &*timings_ : nullptr,
           .sem_ir = &*sem_ir_,
-          .cpp_ast = &cpp_ast_};
+          .clang_ast_unit = &clang_ast_unit_};
 }
 
 auto CompilationUnit::PostCheck() -> void {
diff --git a/toolchain/language_server/context.cpp b/toolchain/language_server/context.cpp
index 21ef5de1ef87..8fe65f74d9a2 100644
--- a/toolchain/language_server/context.cpp
+++ b/toolchain/language_server/context.cpp
@@ -148,13 +148,13 @@ auto Context::File::SetText(Context& context, std::optional<int64_t> version,
 
   SemIR::File sem_ir(tree_.get(), SemIR::CheckIRId(0), tree_->packaging_decl(),
                      *value_stores_, uri_.file().str());
-  std::unique_ptr<clang::ASTUnit> cpp_ast;
+  std::unique_ptr<clang::ASTUnit> clang_ast_unt;
   // TODO: Support cross-file checking when multiple files have edits.
   llvm::SmallVector<Check::Unit> units = {{{.consumer = &consumer,
                                             .value_stores = value_stores_.get(),
                                             .timings = nullptr,
                                             .sem_ir = &sem_ir,
-                                            .cpp_ast = &cpp_ast}}};
+                                            .clang_ast_unit = &clang_ast_unt}}};
 
   auto getter = [this]() -> const Parse::TreeAndSubtrees& {
     return *tree_and_subtrees_;
diff --git a/toolchain/lower/file_context.cpp b/toolchain/lower/file_context.cpp
index 3d109fca8af5..0e734be2b851 100644
--- a/toolchain/lower/file_context.cpp
+++ b/toolchain/lower/file_context.cpp
@@ -71,7 +71,7 @@ auto FileContext::PrepareToLower() -> void {
     // Clang code generation should not actually modify the AST, but isn't
     // const-correct.
     cpp_code_generator_->Initialize(
-        const_cast<clang::ASTContext&>(cpp_ast()->getASTContext()));
+        const_cast<clang::ASTContext&>(clang_ast_unit()->getASTContext()));
   }
 
   // Lower all types that were required to be complete.
@@ -158,7 +158,7 @@ auto FileContext::Finalize() -> void {
     // Clang code generation should not actually modify the AST, but isn't
     // const-correct.
     cpp_code_generator_->HandleTranslationUnit(
-        const_cast<clang::ASTContext&>(cpp_ast()->getASTContext()));
+        const_cast<clang::ASTContext&>(clang_ast_unit()->getASTContext()));
     bool link_error = llvm::Linker::linkModules(
         /*Dest=*/llvm_module(),
         /*Src=*/std::unique_ptr<llvm::Module>(
@@ -174,7 +174,7 @@ auto FileContext::Finalize() -> void {
 
 auto FileContext::CreateCppCodeGenerator()
     -> std::unique_ptr<clang::CodeGenerator> {
-  if (!cpp_ast()) {
+  if (!clang_ast_unit()) {
     return nullptr;
   }
 
@@ -185,7 +185,7 @@ auto FileContext::CreateCppCodeGenerator()
   cpp_code_gen_options_.EmitVersionIdentMetadata = false;
 
   return std::unique_ptr<clang::CodeGenerator>(clang::CreateLLVMCodeGen(
-      cpp_ast()->getASTContext().getDiagnostics(),
+      clang_ast_unit()->getASTContext().getDiagnostics(),
       clang_module_name_stream.TakeStr(), context().file_system(),
       cpp_header_search_options_, cpp_preprocessor_options_,
       cpp_code_gen_options_, llvm_context()));
diff --git a/toolchain/lower/file_context.h b/toolchain/lower/file_context.h
index aae263ad6744..0987f87e5bfa 100644
--- a/toolchain/lower/file_context.h
+++ b/toolchain/lower/file_context.h
@@ -106,7 +106,9 @@ class FileContext {
     return *cpp_code_generator_;
   }
   auto sem_ir() const -> const SemIR::File& { return *sem_ir_; }
-  auto cpp_ast() -> const clang::ASTUnit* { return sem_ir().cpp_ast(); }
+  auto clang_ast_unit() -> const clang::ASTUnit* {
+    return sem_ir().clang_ast_unit();
+  }
   auto inst_namer() -> const SemIR::InstNamer* { return inst_namer_; }
   auto global_variables() -> const Map<SemIR::InstId, llvm::GlobalVariable*>& {
     return global_variables_;
diff --git a/toolchain/sem_ir/diagnostic_loc_converter.cpp b/toolchain/sem_ir/diagnostic_loc_converter.cpp
index 2a1b404d1cbb..8ddf7dda75b1 100644
--- a/toolchain/sem_ir/diagnostic_loc_converter.cpp
+++ b/toolchain/sem_ir/diagnostic_loc_converter.cpp
@@ -126,7 +126,7 @@ auto DiagnosticLocConverter::ConvertWithImports(LocId loc_id,
 
   // Convert the C++ import locations.
   if (final_node_id.check_ir_id() == SemIR::CheckIRId::Cpp) {
-    const clang::ASTUnit* ast = sem_ir_->cpp_ast();
+    const clang::ASTUnit* ast = sem_ir_->clang_ast_unit();
     // Collect the location backtrace that Clang would use for an error here.
     ClangImportCollector(ast->getLangOpts(),
                          ast->getDiagnostics().getDiagnosticOptions(),
@@ -174,8 +174,8 @@ auto DiagnosticLocConverter::ConvertImpl(
   clang::SourceLocation clang_loc =
       sem_ir_->clang_source_locs().Get(clang_source_loc_id);
 
-  CARBON_CHECK(sem_ir_->cpp_ast());
-  const auto& src_mgr = sem_ir_->cpp_ast()->getSourceManager();
+  CARBON_CHECK(sem_ir_->clang_ast_unit());
+  const auto& src_mgr = sem_ir_->clang_ast_unit()->getSourceManager();
   clang::PresumedLoc presumed_loc = src_mgr.getPresumedLoc(clang_loc);
   if (presumed_loc.isInvalid()) {
     return Diagnostics::ConvertedLoc();
diff --git a/toolchain/sem_ir/file.cpp b/toolchain/sem_ir/file.cpp
index d690661067ac..2dc2d76b0eb8 100644
--- a/toolchain/sem_ir/file.cpp
+++ b/toolchain/sem_ir/file.cpp
@@ -150,9 +150,10 @@ auto File::CollectMemUsage(MemUsage& mem_usage, llvm::StringRef label) const
   mem_usage.Collect(MemUsage::ConcatLabel(label, "types_"), types_);
 }
 
-auto File::set_cpp_ast(clang::ASTUnit* cpp_ast) -> void {
-  cpp_ast_ = cpp_ast;
-  clang_mangle_context_.reset(cpp_ast->getASTContext().createMangleContext());
+auto File::set_clang_ast_unit(clang::ASTUnit* clang_ast_unit) -> void {
+  clang_ast_unit_ = clang_ast_unit;
+  clang_mangle_context_.reset(
+      clang_ast_unit->getASTContext().createMangleContext());
 }
 
 }  // namespace Carbon::SemIR
diff --git a/toolchain/sem_ir/file.h b/toolchain/sem_ir/file.h
index f22a9d3883e2..90ef2813329a 100644
--- a/toolchain/sem_ir/file.h
+++ b/toolchain/sem_ir/file.h
@@ -194,12 +194,14 @@ class File : public Printable<File> {
   }
   auto import_cpps() -> ImportCppStore& { return import_cpps_; }
   auto import_cpps() const -> const ImportCppStore& { return import_cpps_; }
-  auto cpp_ast() -> clang::ASTUnit* { return cpp_ast_; }
-  auto cpp_ast() const -> const clang::ASTUnit* { return cpp_ast_; }
+  auto clang_ast_unit() -> clang::ASTUnit* { return clang_ast_unit_; }
+  auto clang_ast_unit() const -> const clang::ASTUnit* {
+    return clang_ast_unit_;
+  }
   // TODO: When the AST can be created before creating `File`, initialize the
   // pointer in the constructor and remove this function. This is part of
   // https://github.com/carbon-language/carbon-lang/issues/4666
-  auto set_cpp_ast(clang::ASTUnit* cpp_ast) -> void;
+  auto set_clang_ast_unit(clang::ASTUnit* clang_ast_unit) -> void;
   auto clang_mangle_context() -> clang::MangleContext* {
     return clang_mangle_context_.get();
   }
@@ -335,10 +337,10 @@ class File : public Printable<File> {
 
   // The Clang AST to use when looking up `Cpp` names. Null if there are no
   // `Cpp` imports.
-  clang::ASTUnit* cpp_ast_ = nullptr;
+  clang::ASTUnit* clang_ast_unit_ = nullptr;
 
   // The Clang mangle context for the target in the ASTContext. Initialized
-  // together with `cpp_ast_`.
+  // together with `clang_ast_unit_`.
   std::unique_ptr<clang::MangleContext> clang_mangle_context_;
 
   // Clang AST declarations pointing to the AST and their mapped Carbon