[support] What is difference of Theme and engine and template

Hi , I am using box_cleanslate_smarty theme . But I am very new to this world . I do not have clear concepts of Theme and engine and template . Where I can find good material ? After googling I got this things . http://drupal.org/node/11774 http://drupal.org/book/export/html/509 Thanks in advance -- Amit. ______________________________________________________ param vaibhavam netum etat swaraashtram   samrthaa bhavatwaashishaa tebhrusham            || Bharat Maata Ki Jay ||