i want to know if i can name my son islam and what is the exact meaning

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

It is better not to name your child with the name Islam as this word is of great status. A person might be given this name but when he grows up, he acts contrarily to the teachings and principles of Islam. It is for this reason that some jurists stated that it is disliked to name children with names such as Noorud-Deen [the light of the religion], Dhiyaa’ Ad-Deen [the brightness of the religion], Sayful-Islaam [the sword of Islam], Nourul-Islaam [the light of Islam], etc. They stated that a person who is named with one of these names could act contrarily to Islam and be an enemy of Islam when he grows up while his name is Naasirud-Deen [the supporter of the religion]. 

Allaah Knows best.