$parse = json_decode('[["name","lastname","age","color","size"],["name2","lastname2","age2","color2","size2"],["name3","lastname3","age3","color3","size3"]]');
print_r($parse);

Array (     [0] => Array         (             [0] => name             [1] => lastname             [2] => age             [3] => color             [4] => size         )      [1] => Array         (             [0] => name2             [1] => lastname2             [2] => age2             [3] => color2             [4] => size2         )      [2] => Array         (             [0] => name3             [1] => lastname3             [2] => age3             [3] => color3             [4] => size3         )  )

echo $parse[0][0]; // Şeklinde kullanabilirsinde