Virtual = the appearance without the physical similarities. I have made a virtual environment where I can be someone else on the computer. My avatar is a mouse-man. I eat virtual cheese in my computer world.

Here is the dictionary definition of the word virtual: 1. Existing or resulting in essence or effect though not in actual fact, form, or name: Example: The virtual extinction of the buffalo. 2. Existing in the mind, especially as a product of the imagination. Used in literary criticism of a text. 3. Computer Science created, simulated, or carried on by means of a computer or computer network: virtual conversations in a chatroom.

There is a very good way to tell the difference. If you hear the world virtual then in this situation it means not realistic. Example: I went to see a virtual reality movie yesterday. But if you see the word virtually, this means truth or fact. Example: There is virtually no homeless people in Alaska. Hope that helps!