Question

what do you mean by a Trojan virus ?

Answer 1

it is a type of  malware  designed  to provide  unauthorised remote access to a      user 's   computer

Answer 2

Trojan Horse are simple programs that pretend to be useful applications while they always do something destructive.They are not self replicating.A Trojan can spread only when it is copied to another system.The name "Trojan Horse" came from the wooden horse used by the Greek Army to conquer the city of Troy.