| Word | Description |
| Script | The series of instructions that can be interpreted by program, sometimes referred to as macros. |
| SD RAM (static dynamic RAM) | A type of random access memory (RAM) that offers comparatively short access time. |
| Search engine | An Internet-based program that returns a list of web pages that contain the search terms entered by the user into a search form. |
| Security | Involves ensuring that private information stays private. It also entails protecting your computer from viruses. The use of passwords, anti-virus software and firewalls are three examples of common security measures. |
| Security gateway | A security layer, which fortifies the network against hostile virus attacks by screening incoming executables files and data. |
| Server | Computers that run web sites and email services, and are connected to the Internet 24 hours a day. |
| SET (secure electronic transaction) | A standard means of securing payment transaction made to online merchants. |
| Skype | A program that can be downloaded from the Internet, and allows you to phone people, either via the Skype network or their conventional phone line. Skype also advises you when employees, friends or contacts are online, which allows you to chat to them online. You can also send messages, documents and files directly to their computers. |
| Smart card | The term used to describe the use of a sniffer program to monitor data traffic to a network or server, in order to gain access to information. |
| Sniffing | The term used to describe the use of a sniffer program to monitor data traffic to a network or server, in order to gain access to information. |
| Software | The programs and applications that run on a computer. Examples include word processors, spreadsheets, and databases. |
| SPAM | Unsolicited or junk email. |
| Spoofing | When an email message appears to come from a legitimate source but in fact is from an impostor. Email spoofing can be used for malicious purposes such as trawling for sensitive business data and other industrial espionage activities. |
| SPX/IPX | A network protocol. |
| SSL (Secure Sockets Layer) | A protocol that is commonly used for managing the security of data transmissions over the Internet. |
| Supply chain (value chain) | A chain or progression beginning with raw material and ending with the sale of the finished product or service. |
| Surfing | Using a browser to visit sites on the Internet. |