• Python

PLANET = 'Earth'

• Ada

planet : constant String := "Earth";

• C

const char *_planet = "Earth";

• Clojure

(def planet "Earth")

• C++

// using char*
constexpr char planet[] = "Earth";

// using string
const std::string planet{"Earth"};

• C#

const string _planet = "Earth";

• D

enum string planet = "Earth";

• D

const string planet = "Earth";

• D

enum planet = "Earth";

• D

immutable string planet = "Earth";

• D

static immutable string planet = "Earth";

• Dart

const String _planet = "Earth";

• Elixir

planet = "Earth"

• Erlang

Planet = "Earth".

• Fortran

character(*), parameter :: planet = "Earth"

• Fortran

  character(len=*), parameter :: planet = "Earth"

• Go

const planet = "Earth"

• Groovy

static final planet = "Earth"
static final planet = 'Earth'
static final planet = /Earth/
static final planet = '''Earth'''
static final planet = """Earth"""

• Haskell

planet = "Earth"

• JS

const planet = 'Earth'

• Java

final String planet = "Earth";

• Java

final String planet = "Earth";

• Java

static final String planet = "Earth";

• Kotlin

val planet = "Earth"

• Lisp

(defparameter +planet+ "Earth")

• Lua

PLANET = "Earth"

• Obj-C

NSString * const Planet=@"Earth";

• PHP

const PLANET = 'Earth';

• PHP

define('PLANET', 'Earth');

• Pascal

const
  planet = 'Earth';

• Perl

use constant planet => 'Earth';
use constant PI => 3.14159;
use constant { RED => 1, BLUE => 2, GREEN => 3 };

• Perl

const my $planet => 'Earth';

• Ruby

Planet = 'Earth'

• Rust

const PLANET: &str = "Earth";

• Scala

val planet = "Earth"

• Smalltalk

planet := 'Earth'.

• VB

Const PLANET = "Earth"