Declare anywhere is a style of programming opposite of AlgolLanguage/PascalLanguage style syntax where variables are clearly declared separate from code.

An example is in C++ where one can declare things anywhere he wishes on the spot.

Another example is languages which have no type system such as PHP (in fact you don't even declare anything, you just put crap all over the screen wherever you wish and add source comments to fake the type system in by using TypeSystemThroughComments ;) )