Knowledge base
Security glossary
Plain-English definitions for the acronyms and jargon small and mid-sized businesses run into — email authentication, web security, identity, compliance, and the threats behind them. 47 terms, each linked to the tools that act on it.
Type at least 2 characters to filter. Searches terms, definitions, and synonyms.
Email authentication
- BIMIShows your verified logo next to your name in inboxes.
- DKIMCryptographic signature proving an email wasn't tampered with.
- DMARCTells mailbox providers what to do with mail that fails authentication.
- MTA-STSForces TLS encryption for incoming mail to your domain.
- SPFLists which servers are allowed to send mail from your domain.
- TLS-RPTAsks sending servers to report TLS-delivery failures to you.
- VMCCertificate that lets your trademarked logo appear via BIMI.
Web security
- CAA recordDNS record naming which CAs may issue certs for your domain.
- ClickjackingHiding your site in an invisible frame to hijack clicks.
- CORSBrowser rules for which sites may read another site's responses.
- CSPHeader that controls what a page is allowed to load and run.
- CSRFTricking a logged-in user's browser into a state-changing request.
- DNSSECSigns your DNS records so they can't be forged in transit.
- HSTSHeader that forces browsers to use HTTPS for your site.
- SameSite cookieCookie flag limiting when cookies ride cross-site requests.
- Security headersHTTP response headers that tell browsers how to defend your site.
- XSSInjecting attacker script into a page other users will load.
Identity & access
- Least privilegeGive each account only the access it actually needs.
- MFASecond factor (code, key, or biometric) on top of a password.
- PasskeyPhishing-resistant credential bound to your device (Touch ID, etc.).
- Phishing-resistant MFAMFA that can't be relayed by a fake login page.
- SSOOne login that grants access to many connected apps.
- TOTPTime-based one-time password from an authenticator app.
Threats & general security
- Backup (3-2-1)Recoverable copies of your data, kept where ransomware can't reach.
- BECEmail fraud impersonating an executive or vendor to steal money.
- CVEA public catalog ID for one specific known vulnerability.
- CVSSA 0–10 score rating how severe a vulnerability is.
- Patch managementKeeping software current so known holes get closed.
- PhishingFraudulent messages that trick people into handing over access.
- RansomwareMalware that encrypts your data and demands payment to release it.
- RTO / RPOHow fast you must recover, and how much data you can lose.
- Spear phishingA phishing attack tailored to one specific person.
- Vulnerability scanningAutomated checks that surface known weaknesses in your systems.
- Zero-dayA vulnerability exploited before a patch exists.
Compliance & privacy
- CMMCDoD cybersecurity standard for defense-industrial-base companies.
- GDPREU law governing how personal data is collected and used.
- NIST CSFCybersecurity framework: Govern · Identify · Protect · Detect · Respond · Recover.
- PCI DSSCard-industry security standard for anyone handling card data.
- PIIData that identifies a specific person.
- SOC 2Audit report customers ask for to prove you handle their data safely.
Encryption & transport
Resolute platform
Looking for product FAQs instead? The help center covers pricing, integrations, and troubleshooting. To run a free check on your own domain, start with the email scan.