Lista de Meses do Ano no formato Array();

array-meses.php

<?php
$meses = array(
  "Jan" => 1, 
  "Fev" => 1, 
  "Mar" => 3, 
  "Abr" => 4, 
  "Mai" => 5, 
  "Jun" => 6, 
  "Jul" => 7, 
  "Ago" => 8, 
  "Set" => 9, 
  "Out" => 10, 
  "Nov" => 11, 
  "Dez" => 12
);

$meses = array(
   1 => "Jan", 
   2 => "Fev", 
   3 => "Mar", 
   4 => "Abr", 
   5 => "Mai", 
   6 => "Jun", 
   7 => "Jul", 
   8 => "Ago", 
   9 => "Set", 
   10 => "Out", 
   11 => "Nov", 
   12 => "Dez"
);