What is the meaning of "Raksha Bandhan"

Hello,Chandu! Raksha Bandhan is celebrated by the Hindus on the Shravana Purnima day.it signifies the love of a sister to her brother.she ties the sacred ornamental thread on the right wrist of her brother with a request to protect her from all abuse of the society and in return the brother promise her to protect her in lieu of his life.Even the Hindu sister tie this thread in the hands of Muslim brothers who actually have protected the Hindu sister's life putting his life in dangers.there are several instances.thanx.