The word virtual in modern Russian means "occurring or existing in a fictitious world", and as a rule it is a question of the Internet or computer model. Often the word "virtual" is an antonym to the word "real". But it is best to understand its meaning from the context:
"Virtual reality" is a model of the world that exists in the computer and sometimes interacts with the real world. The most common example is the virtual reality glasses, in which the user sees a three-dimensional drawn world.
"Virtual novel" is a correspondence on the Internet without communication in real life. Often virtual novels turn into real ones, but this does not save marriages from divorce :)
"Virtual Tour" is a computer presentation from photos or videos, allowing you to "walk" around the city or building using interactive control buttons.