It is more common that people do not know the difference between the antivirus products and the internet security suites.
The main difference is that the standard antivirus product offers protection against the following dangers: Malware, Viruses, Trojans, Spyware, Worms, Bots and often the product also scans the local files on the computer.
The Internet Security suites are products that offer more possibilities for everything that comes in via the internet. For example, this product scans all emails, acts as a spam filter, identity check, parental control, password monitoring, real-time notifications, anti-rootkits and anti-phising.
You will see that the Internet Security suite can do much more than the standard antivirus software. Which also makes security much better. Often the sales prices of the Internet Security suites are also higher than those of the antivirus software.