Searchable glossary of 500+ cybersecurity acronyms and terms with definitions, related concepts, and RFC references.
A searchable glossary of 500+ cybersecurity acronyms and terms. Type an acronym or a full term and the tool returns the expansion, a plain-language definition, related concepts, and, where the term is defined by a standards document, the RFC reference. Lookup happens in the browser, so results appear instantly and the glossary still works offline. The thing people most often get wrong: an acronym can have several expansions, and the glossary records the meaning used in security contexts, so match the entry against where you actually saw the term.
A concrete input and expected output from the current implementation.
Input
TLS
Expected output
Transport Layer Security - the cryptographic protocol that encrypts and authenticates communication between two endpoints, and the successor to the older Secure Sockets Layer (SSL). Related concepts: SSL (predecessor), DTLS (Datagram Transport Layer Security, the variant for datagram transports such as UDP), HTTPS (HTTP carried over TLS), certificate, cipher suite. RFC references: RFC 8446 (TLS 1.3), RFC 5246 (TLS 1.2).
TLS has one dominant expansion in this domain, so the entry leads with it and then anchors the definition with the protocol's defining documents: RFC 8446 for the current 1.3 version and RFC 5246 for the long-deployed 1.2 version, plus the related terms a reader meets in the same context.
Type an acronym, a partial string, or a full term and the tool filters the glossary to matching entries. Case does not matter, so TLS and tls behave identically, and entries whose expansion contains your text show up alongside direct matches. When the index is large, the list is a starting point; click into an entry for the full definition, related concepts, and RFC references.
Each entry shows the expansion, a short definition written in plain language rather than spec prose, and related-concepts links that cross-reference other entries in the glossary. Where the term is defined by an IETF standard, an RFC reference names the defining document, so TLS points at RFC 8446 and RFC 5246 and you can go to the source instead of trusting the summary.
Not necessarily. The glossary covers 500+ commonly used terms, but vendor-specific names and very recent coinages are often missing. Try searching the full expansion if you know it, and if the term came from a real document or product, treat that source as authoritative rather than assuming the glossary is complete.
Yes for a plain-language explanation, with a caveat: entries are summaries written for quick reference, not normative text. For standards-defined terms, cite the linked RFC, which is the authoritative specification. If you need exact wording, algorithm requirements, or version details, quote the RFC rather than the glossary entry.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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