The word ‘pooja’ comes from two words 'Poo' and 'Ja'. ‘Poo’ means ‘poornatha’, fullness. ‘Ja’ means ‘born out of’. That which is born out of fullness is pooja. When your consciousness becomes so full and in that state when you do an action that is known as pooja. When heart is full and you are overwhelmed, when an action is done out of that overwhelming state and gratitude is expressed, that is known as pooja.
Puja is worshipping the almighty Divine powers. Puja is the showing of your reverence to the God. Puja is an act of having a connection to the divine. During the Puja the deity's cosmic energy is prayed to be come down through the chanting of Mantras, Stotras, Yoga.