SQL Server error: Incorrect syntax near the keyword 'User'

i get an error which says incorrect syntax near keyword user at the com.executequery line when i run this code. what am i doing wrong?

internal bool IsThereRegisteredUser()
{

    SqlConnection m = new SqlConnection();
    m.ConnectionString = @"Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\UserDatabase.mdf;Integrated Security=True";
    m.Open();
    string query = @"SELECT COUNT(username) FROM user";
    SqlCommand com = new SqlCommand(query, m);
    //SqlDataReader h = new SqlDataReader();
    //h = com.ExecuteReader();
    //h.Read();

    int userNum = com.ExecuteNonQuery();

    if (userNum > 1)
    {
        return true;
    }
    else
    {
        return false;
    }
}