Eric answer is correct, but the problem is the fields are not grouped. Imagine you have multiple streets and cities which belong together:
<h1>First Address</h1>
<input name="street[]" value="Hauptstr" />
<input name="city[]" value="Berlin" />
<h2>Second Address</h2>
<input name="street[]" value="Wallstreet" />
<input name="city[]" value="New York" />
The outcome would be
$POST = [ 'street' => [ 'Hauptstr', 'Wallstreet'],
'city' => [ 'Berlin' , 'New York'] ];
To group them by address, I would rather recommend to use what Eric also mentioned in the comment section:
<h1>First Address</h1>
<input name="address[1][street]" value="Hauptstr" />
<input name="address[1][city]" value="Berlin" />
<h2>Second Address</h2>
<input name="address[2][street]" value="Wallstreet" />
<input name="address[2][city]" value="New York" />
The outcome would be
$POST = [ 'address' => [
1 => ['street' => 'Hauptstr', 'city' => 'Berlin'],
2 => ['street' => 'Wallstreet', 'city' => 'New York'],
]
]