Namespace, But Far In The Name

<?php

// Not allowed
namespace namespace {}

//syntax error, unexpected namespace-relative name "namespace\A", expecting "{"
namespace namespace\A {}

// namespace may be used, but not in first position
// surely, not a good idea
namespace A\namespace {
    const B = 1;
}

namespace A {
    echo namespace\namespace\B;
}

?>

Namespaces can be named anything, except namespace. That keyword is used as a prefix, on a name (class, function, constant, etc.) to represent the current namespace, and allow for relative sub-namespaces.

Then, the namespace keyword cannot be used as the first part of a namespace, as it would conflict with the namespace relative part.

But it is possible to use namespace later in the name.

See Also

• namespace (PHP manual)

• namespace in a namespace [Try me]

PHP Error Messages

• Cannot use ‘namespace’ as namespace name

PHP Features

• namespace

• keyword

Last updated: 14 July 2026