Lord Shiva named the boy Ganapati, which means commander of his troops.

Once upon a time Mother Parvati wished to take a bath. She created a boy from the dirt of her body and asked him to stand guard outside while she cleansed herself. Meanwhile, Lord Shiva returned home. When he tried to enter the house, the boy prevented him from doing so. In anger, Shiva cut off the boy's head. When Parvati saw this, she burst into tears. In order to console her, Shiva sent out his troops (gaNa) to fetch the head of anyone found sleeping with his head pointing to the north. They found an elephant sleeping thus and brought back its head. Shiva then attached the elephant's head to the body of the boy and revived him. He named the boy Ganapati, which means commander of his troops. He granted him a boon that everyone would worship him (Ganesha) before beginning any work. 
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