Trojan horse - Definition from the Hotspot Shield Glossary
A Trojan Horse is a type of computer virus. It is named after the historical Horse that the Greeks created to infiltrate the Trojan settlement of Troy.
A Trojan is a malicious program that gains access to a computer by misleading a user and hiding its true purpose and intent - The Trojan Horse may seem harmless, but infact when it gains access to your computer, it will unleash a deadly virus that could be harmful to your device. Generally a Trojan horse will be dispersed by social engineering - Maybe an attachment in an email or a .exe file. While Trojan’s generally don’t duplicate themselves to slow down system resources like other viruses, they instead can open backdoor connection that the author of the virus will exploit to gain access to your personal data. Furthermore Trojan Horses once inside your computer can crash your device, delete files and corrupt data.