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 | finally (as of PHP 5.5) | 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 (as of PHP 5.5) |  |  |

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) |  |  |  |