| Full form of VPN | Virtual Private Network |
| What DNS stands for | Domain Name System |
| What 2FA adds to a password | A second verification step (e.g., a one-time code) |
| What E2EE prevents | Service providers from reading your messages |
| What a data broker sells | Personal information collected from public and commercial sources |
| Cookie types to know | First-party (functional) and third-party (tracking) |
Why a privacy glossary matters
Online privacy discussions move fast, and the vocabulary moves with them. Terms like "end-to-end encryption" or "VPN" appear in news articles, app settings, and product descriptions without much explanation. When you cannot decode the language, it becomes difficult to judge whether a tool actually protects you or just sounds like it does.
This glossary collects the terms that come up most often when people learn about online safety. Each definition focuses on the practical meaning rather than the technical mechanism. If you want to go deeper on specific tracking techniques, see how cookies, trackers, and fingerprinting work. When you are ready to apply these concepts to your own setup, the personal privacy audit checklist walks through your accounts, apps, and browser settings in one session.
End-to-end encryption
A method of protecting messages so that only the sender and recipient can read them. The service carrying the message cannot decrypt the content.
VPN
A service that routes your internet traffic through a remote server, hiding your IP address from sites you visit. It reduces one form of tracking but does not make you fully anonymous.
Phishing
An attack that uses a fake message posing as a trusted source to steal login credentials, financial data, or personal information.
Two-factor authentication
A login process that requires two forms of verification: your password and a second factor such as a one-time code. It limits damage if your password is exposed.
DNS
The system that converts website names into numeric addresses computers can use. DNS queries can be logged and used to build a record of which sites you visit.
Data broker
A company that gathers personal information from many sources and sells it to third parties, often without the individual's awareness or consent.
Metadata
Descriptive information about a communication or file, such as timestamps, sender, and recipient, rather than the actual content.
Zero-day vulnerability
A software security flaw that is unknown to the developer or unpatched at the time it is discovered and potentially exploited by attackers.
Cookies
Small data files stored in your browser by websites. First-party cookies support site functions; third-party cookies placed by ad networks can track you across the web.
Browser fingerprinting
A tracking method that identifies your device by combining details such as screen size, installed fonts, and browser version, without using cookies or asking for permission.
Encryption
The process of converting readable data into a scrambled format that requires a key to decode. Used to protect stored files and data in transit.
IP address
A numeric label assigned to your device on a network. Websites can log it to estimate your location and identify your internet service provider.
Core terms from A to Z
The definitions below are grouped into two categories for easier scanning: network and data terms, then security and threat terms. Both sets appear in everyday privacy conversations, so it is worth reading across both.
Network and data terms
DNS (Domain Name System) translates human-readable addresses (like example.com) into numeric IP addresses that computers use to route traffic. Your DNS queries can reveal every site you visit, even when the page itself is encrypted. Encrypted DNS services such as DNS-over-HTTPS address this gap.
IP address is a numeric label assigned to your device on a network. Websites you visit can log your IP address, which can be used to estimate your approximate location and identify your internet service provider.
VPN (Virtual Private Network) routes your internet traffic through a server operated by the VPN provider, masking your IP address from the sites you visit. It does not make you anonymous and does not protect you from tracking by cookies or fingerprinting.
Metadata is data about data. An email's metadata includes who sent it, when, and to whom, even if the message body is encrypted. Metadata can reveal communication patterns without exposing content.
Cookies are small text files a website stores in your browser to remember you between visits. First-party cookies support basic functions like keeping you logged in. Third-party cookies placed by advertisers track you across many unrelated sites.
Security and threat terms
End-to-end encryption (E2EE) scrambles a message so that only the sender and the intended recipient can read it. The service provider cannot read the content in transit or at rest on its servers.
Phishing is a social engineering attack in which a message, often an email or text, impersonates a trusted source to trick you into handing over credentials or clicking a malicious link.
Two-factor authentication (2FA) requires a second form of verification beyond your password, such as a code sent to your phone or generated by an app. Even if your password is compromised, 2FA can stop unauthorized access.
Zero-day vulnerability is a software flaw that has no available patch because the developer is not yet aware of it, or has not had time to fix it. Attackers who discover zero-days can exploit them before any defense is in place.
Data broker is a company that collects personal information from public records, purchase histories, and online behavior, then sells or licenses that information, often without the individual's direct knowledge.
| Full form of VPN | Virtual Private Network |
| What DNS stands for | Domain Name System |
| What 2FA adds to a password | A second verification step (e.g., a one-time code) |
| What E2EE prevents | Service providers from reading your messages |
| What a data broker sells | Personal information collected from public and commercial sources |
| Cookie types to know | First-party (functional) and third-party (tracking) |