While most religions are named after a person or a group of people, the word Islam actually describes the spiritual state of the believer. The word Islam means Submission, Submission to the will of God, and a Muslim is a person who strives to live in a state of Islam, to live life in a way that is pleasing to God. If you think about it, that's pretty much the goal of all religions, which is interesting, because Islam is seen by Muslims as being the original religion given by God to humanity.
Islam is understood to be the natural state of human existence. At birth, we are in a completely pure and natural state, aware of God and in sync with God's will. This innate nature we possess is known as our Fitra. This is why, according to Islamic belief, we are all born as Muslims. Though we learn a particular tradition as we grow up, that Fitra remains within us. Whether we call it our conscience, or moral intuition, it's the reason we all know deep down that God exists, that we recognize basic right and wrong. For this reason, when someone who was not raised as a Muslim decides to embrace Islam, they are referred to not as a convert but as a revert, because they are returning the natural state in which they were born, recognizing and embracing their Fitra.
Islam is not a part-time religion, something you do once a week or only on holidays. Islam is 24 hours a day, 7 days a week, 365 days a year. Islam influences everything we do, every choice we make, the way we interact with others, even the way we appreciate the world around us. So Islam is much more than just a religion. It is a complete deen, which is an Arabic word often translated as religion, but which truly means "way of life."
Now you might be asking yourself, "If Islam is Submission to God's will, how can I know that I'm living my life the way God wants me to live?" InshaAllah, God willing, we'll address that in the upcoming post on "Prophets."
"This day I have perfected for you your religion, completed My favor upon you and have chosen for you Islam as your religion."