List of Reserved Words
Predefined Classes
List of Reserved Words
PHP Manual

## List of Keywords

These words have special meaning in PHP. Some of them represent things which look like functions, some look like constants, and so on - but they're not, really: they are language constructs. You cannot use any of the following words as constants, class names, function or method names. Using them as variable names is generally OK, but could lead to confusion.

PHP Keywords
__halt_compiler | abstract | and | array | as
break | callable (as of PHP 5.4) | case | catch | class
clone | const | continue | declare | default
die | do | echo | else | elseif
empty | enddeclare | endfor | endforeach | endif
endswitch | endwhile | eval | exit | extends
final | for | foreach | function | global
goto (as of PHP 5.3) | if | implements | include | include_once
instanceof | insteadof (as of PHP 5.4) | interface | isset | list
namespace (as of PHP 5.3) | new | or | print | private
protected | public | require | require_once | return
static | switch | throw | trait (as of PHP 5.4) | try
unset | use | var | while | xor
yield |  |  |  |

Compile-time constants
__CLASS__ | __DIR__ (as of PHP 5.3) | __FILE__ | __FUNCTION__ | __LINE__ | __METHOD__
__NAMESPACE__ (as of PHP 5.3) | __TRAIT__ (as of PHP 5.4) |  |  |  |