diff --git a/.changelog/38509.txt b/.changelog/38509.txt
new file mode 100644
index 00000000000..9185b5ba035
--- /dev/null
+++ b/.changelog/38509.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_cloudsearch_domain: Fix `index_name` character length validation
+```
diff --git a/internal/service/cloudsearch/domain.go b/internal/service/cloudsearch/domain.go
index ae6dff5ded5..5b12cf918db 100644
--- a/internal/service/cloudsearch/domain.go
+++ b/internal/service/cloudsearch/domain.go
@@ -126,7 +126,7 @@ func resourceDomain() *schema.Resource {
 						"source_fields": {
 							Type:         schema.TypeString,
 							Optional:     true,
-							ValidateFunc: validation.StringDoesNotMatch(regexache.MustCompile(`score`), "Cannot be set to reserved field score"),
+							ValidateFunc: validation.StringDoesNotMatch(scoreRegex, "Cannot be set to reserved field score"),
 						},
 						names.AttrType: {
 							Type:             schema.TypeString,
@@ -145,7 +145,7 @@ func resourceDomain() *schema.Resource {
 				Type:         schema.TypeString,
 				Required:     true,
 				ForceNew:     true,
-				ValidateFunc: validation.StringMatch(regexache.MustCompile(`^[a-z]([0-9a-z-]){2,27}$`), "Search domain names must start with a lowercase letter (a-z) and be at least 3 and no more than 28 lower-case letters, digits or hyphens"),
+				ValidateFunc: validation.StringMatch(nameRegex, "Search domain names must start with a lowercase letter (a-z) and be at least 3 and no more than 28 lower-case letters, digits or hyphens"),
 			},
 			"scaling_parameters": {
 				Type:     schema.TypeList,
@@ -181,6 +181,12 @@ func resourceDomain() *schema.Resource {
 	}
 }
 
+var (
+	indexNameRegex = regexache.MustCompile(`^(\*?[a-z][0-9a-z_]{2,63}|[a-z][0-9a-z_]{0,63}\*?)$`)
+	nameRegex      = regexache.MustCompile(`^[a-z]([0-9a-z-]){2,27}$`)
+	scoreRegex     = regexache.MustCompile(`score`)
+)
+
 func resourceDomainCreate(ctx context.Context, d *schema.ResourceData, meta interface{}) diag.Diagnostics {
 	var diags diag.Diagnostics
 	conn := meta.(*conns.AWSClient).CloudSearchClient(ctx)
@@ -485,9 +491,9 @@ func resourceDomainDelete(ctx context.Context, d *schema.ResourceData, meta inte
 func validateIndexName(v interface{}, k string) (ws []string, es []error) {
 	value := v.(string)
 
-	if !regexache.MustCompile(`^(\*?[a-z][0-9a-z_]{2,63}|[a-z][0-9a-z_]{2,63}\*?)$`).MatchString(value) {
+	if !indexNameRegex.MatchString(value) {
 		es = append(es, fmt.Errorf(
-			"%q must begin with a letter and be at least 3 and no more than 64 characters long", k))
+			"%q must begin with a letter and be at least 1 and no more than 64 characters long", k))
 	}
 
 	if value == "score" {
diff --git a/internal/service/cloudsearch/domain_test.go b/internal/service/cloudsearch/domain_test.go
index 8215cdcabb6..be498610647 100644
--- a/internal/service/cloudsearch/domain_test.go
+++ b/internal/service/cloudsearch/domain_test.go
@@ -121,7 +121,7 @@ func TestAccCloudSearchDomain_indexFields(t *testing.T) {
 				Config: testAccDomainConfig_indexFieldsUpdated(rName),
 				Check: resource.ComposeAggregateTestCheckFunc(
 					testAccDomainExists(ctx, resourceName, &v),
-					resource.TestCheckResourceAttr(resourceName, "index_field.#", acctest.Ct3),
+					resource.TestCheckResourceAttr(resourceName, "index_field.#", acctest.Ct4),
 					resource.TestCheckTypeSetElemNestedAttrs(resourceName, "index_field.*", map[string]string{
 						names.AttrName:         "literal_test",
 						names.AttrType:         "literal",
@@ -141,6 +141,13 @@ func TestAccCloudSearchDomain_indexFields(t *testing.T) {
 						"analysis_scheme": "_en_default_",
 						"highlight":       acctest.CtTrue,
 					}),
+					resource.TestCheckTypeSetElemNestedAttrs(resourceName, "index_field.*", map[string]string{
+						names.AttrName: "i",
+						names.AttrType: "literal",
+						"return":       acctest.CtTrue,
+						"search":       acctest.CtFalse,
+						"sort":         acctest.CtTrue,
+					}),
 				),
 			},
 		},
@@ -402,6 +409,14 @@ resource "aws_cloudsearch_domain" "test" {
     highlight       = true
     search          = true
   }
+
+  index_field {
+    name   = "i"
+    type   = "literal"
+    return = true
+    search = false
+    sort   = true
+  }
 }
 `, rName)
 }
diff --git a/website/docs/r/cloudsearch_domain.html.markdown b/website/docs/r/cloudsearch_domain.html.markdown
index c41816ef8eb..cf3132cc457 100644
--- a/website/docs/r/cloudsearch_domain.html.markdown
+++ b/website/docs/r/cloudsearch_domain.html.markdown
@@ -74,7 +74,7 @@ This configuration block supports the following attributes:
 
 This configuration block supports the following attributes:
 
-* `name` - (Required) A unique name for the field. Field names must begin with a letter and be at least 3 and no more than 64 characters long. The allowed characters are: `a`-`z` (lower-case letters), `0`-`9`, and `_` (underscore). The name `score` is reserved and cannot be used as a field name.
+* `name` - (Required) A unique name for the field. Field names must begin with a letter and be at least 1 and no more than 64 characters long. The allowed characters are: `a`-`z` (lower-case letters), `0`-`9`, and `_` (underscore). The name `score` is reserved and cannot be used as a field name.
 * `type` - (Required) The field type. Valid values: `date`, `date-array`, `double`, `double-array`, `int`, `int-array`, `literal`, `literal-array`, `text`, `text-array`.
 * `analysis_scheme` - (Optional) The analysis scheme you want to use for a `text` field. The analysis scheme specifies the language-specific text processing options that are used during indexing.
 * `default_value` - (Optional) The default value for the field. This value is used when no value is specified for the field in the document data.