Q:

what is the difference between wordpress category and taxonomy? 

i just want to know that what is the difference between WordPress category and taxonomy.  if you see both works similar so what is the difference. 

A:

In WordPress, a taxonomy is a "way" of categorizing / tagging posts. 
Read the WordPress Taxonomies Docs. 
Categories are a taxonomy.   They are a built-in taxonomy that comes by default. 
Tags are also a taxonomy.   They are built-in also. 
You may also create your own custom taxonomies that follow either a "heirarchical" structure (such as categories) or not (such as tags): Custom Taxonomies

