The meaning of the word quarantine is to "isolate, remove, or regulate the movement of a healthy person who had the potential to be exposed to a biological disease, to see if the person may develop a disease and become ill."
Within computing self replicating programs are referred to as computer viruses. Computer viruses attach themselves to "healthy" computer files, and then modify the file and corrupt it - just as a biological virus spreads from one body cell to another.
To "heal" computer systems infected by a computer virus an anti-virus program is used to detect and remove computer viruses. Computer viruses leave a 'signature' when they modify a computer file, and anti-virus programs detect viruses by scanning every computer file within a computer system and analysing whether any file matches the signature of a computer virus.
When an anti-virus program comes across a file it believes has been modified by a computer virus, it has one of three options:
The quarantine option places the suspect file into an isolated location where it cannot interfere with the day-to-day processes of the computer system. The quarantine option allows the user the time to decide whether to attempt to "heal" the file, reinstate it if they believe it is harmless or to delete the file if it cannot be "healed".