20 Cybersecurity Terms You Keep Hearing and What They Actually Mean

You hear these terms every day — zero-day, CVSS, EDR, zero trust — but most people use them loosely. Getting them wrong isn't just embarrassing in an interview; it can lead to genuinely bad security decisions. This video explains the terms that actually matter, in the order practitioners need to understand them, and — more importantly — the reasoning behind the vocabulary. We start with the interview question that trips up even experienced professionals: what's the difference between a threat, a vulnerability, and a risk? Then we walk the lifecycle of a flaw — from how it gets identified (CVE) to how it's scored (CVSS) to how we predict which flaws will actually be exploited (CISA KEV, FIRST's EPSS). Finally, we decode the attacker behavior and detection architecture terms in incident reports (TTPs, APT, lateral movement, EDR/XDR/MDR) and the design principles people treat as interchangeable (zero trust, least privilege, defense in depth). This isn't a memorization dump. It's the why behind the terminology, sourced from NIST definitions and real security frameworks — so you can use the words correctly and make better decisions. What this video breaks down: • Threat vs. vulnerability vs. risk — the difference that actually matters • CVE vs. CVSS: why an identifier is not a severity rating • How CISA KEV and FIRST's EPSS fix what CVSS can't tell you • Zero-day vs. n-day: the vulnerability that causes most real breaches • Patch vs. mitigation vs. compensating control — and when each is the right call • The attacker vocabulary: TTPs, APT, lateral movement, privilege escalation • IOC vs. IOA: the difference between what you saw and what the attacker is trying to do • EDR, XDR, MDR — which ones are actually defined terms • Zero trust, least privilege, and defense in depth: three things people treat as one Timestamps: 0:00 Why the terms matter (and the interview question everyone gets wrong) 1:12 Threat, vulnerability, and risk — the core distinction 3:40 CVE vs. CVSS: identifier vs. severity 5:05 CISA KEV and FIRST's EPSS — fixing what CVSS can't tell you 6:28 Zero-day vs. n-day: which one causes most breaches 8:02 Patch, mitigation, and compensating controls 10:15 TTPs, APT, and reading incident reports 12:30 Lateral movement and privilege escalation 13:50 IOC vs. IOA 15:10 EDR, XDR, and MDR — what's actually defined 17:20 Zero trust, least privilege, and defense in depth 19:15 Threat hunting and incident response — putting it together 21:30 Subscribe for more cybersecurity concepts explained clearly, from fundamentals to career-level interview prep. Disclaimer: This video is for educational and informational purposes only and does not constitute professional security, compliance, or legal advice. Security decisions should be validated against your organization's specific requirements and applicable regulations. #cybersecurity #cybersecurityforbeginners #cybersecuritybasics #cybersecurityterms #cybersecurityexplained #informationsecurity #cybersecuritytips #threatvulnerabilityrisk