diff --git a/docs/objects.md b/docs/objects.md
index 9e556d1..9756106 100644
--- a/docs/objects.md
+++ b/docs/objects.md
@@ -57,7 +57,7 @@ Equals method should return true if the underlying value is considered to be equ
 Copy() Object
 ```
 
-Copy method should a _new_ copy of the same object. All primitive and composite value types implement this method to return a deep-copy of the value, which is recommended for other user types _(as `copy` builtin function uses this Copy method)_, but, it's not a strict requirement by the runtime.
+Copy method should return a _new_ copy of the object. Builtin function `copy` uses this method to copy values. Default implementation of all runtime types return a deep-copy values, but, it's not a requirement by the runtime.
 
 
 ### Callable Interface
diff --git a/docs/tutorial.md b/docs/tutorial.md
index a652e83..26e4b85 100644
--- a/docs/tutorial.md
+++ b/docs/tutorial.md
@@ -181,7 +181,7 @@ s = "foo"    // ok: this is not mutating the value
              //  but updating reference 's' with another String value
 ```
 
-The composite types (Array, Map) are mutable by default, but, you can make them immutable using `immutable` expression.
+The compound types (Array, Map) are mutable by default, but, you can make them immutable using `immutable` expression.
 
 ```golang
 a := [1, 2, 3]
diff --git a/runtime/vm_assignment_test.go b/runtime/vm_assignment_test.go
index 2ec4201..a4a943c 100644
--- a/runtime/vm_assignment_test.go
+++ b/runtime/vm_assignment_test.go
@@ -47,7 +47,7 @@ func() {
 	expect(t, `a := 10; a /= 2;; out = a`, 5)
 	expect(t, `a := 10; a /= 5 - 3;; out = a`, 5)
 
-	// composite assignment operator does not define new variable
+	// compound assignment operator does not define new variable
 	expectError(t, `a += 4`, "unresolved reference")
 	expectError(t, `a -= 4`, "unresolved reference")
 	expectError(t, `a *= 4`, "unresolved reference")
diff --git a/runtime/vm_module_test.go b/runtime/vm_module_test.go
index 84eaf06..65eb935 100644
--- a/runtime/vm_module_test.go
+++ b/runtime/vm_module_test.go
@@ -76,7 +76,7 @@ func TestUserModules(t *testing.T) {
 		"mod1": `export "foo"`,
 	})
 
-	// export composite types
+	// export compound types
 	expectWithUserModules(t, `out = import("mod1")`, IARR{1, 2, 3}, map[string]string{
 		"mod1": `export [1, 2, 3]`,
 	})