Acronym glossary

AAA — Authentication, Authorization, and Accounting
A framework for proving identity, granting rights, and logging activity on a network.
ACL — Access Control List
Rules that permit or deny traffic or file access.
ADF — Automatic Document Feeder
Printer/scanner tray that pulls sheets for multi-page jobs.
AES — Advanced Encryption Standard
Modern symmetric cipher used by WPA2/WPA3 and many disk tools.
AMD — Advanced Micro Devices, Inc.
CPU vendor with its own socket families.
AP — Access Point
Wireless device that stations associate with.
APFS — Apple File System
Default modern macOS filesystem.
APIPA — Automatic Private IP Addressing
Windows assigns 169.254.0.0/16 when DHCP fails. Link-local, not internet.
ARM — Advanced RISC Machine
CPU architecture common in phones, some laptops, and Apple silicon.
ATX — Advanced Technology Extended
Common full-size desktop motherboard form factor.
AUP — Acceptable Use Policy
Rules for how company systems and internet may be used.
BEC — Business Email Compromise
Fraud that impersonates executives or vendors to steal money or data.
BIOS — Basic Input/Output System
Legacy firmware. Modern PCs use UEFI but techs still say BIOS for firmware setup.
BNC — Bayonet Neill–Concelman
Coax connector with a twist-lock collar. Rare on modern PCs, still on some video/RF gear.
BSOD — Blue Screen of Death
Windows stop error. Treat the stop code as a clue, not a personality trait of the PC.
BYOD — Bring Your Own Device
Personal phones/laptops used for work. Higher risk; MDM often required.
CIFS — Common Internet File System
Older name associated with SMB file sharing.
CMDB — Configuration Management Database
System of record for assets, relationships, and configuration items.
CMOS — Complementary Metal-Oxide Semiconductor
Historically the battery-backed firmware settings memory. Wrong date/time often means a dead motherboard battery.
CNAME — Canonical Name
DNS record that aliases one name to another.
CPU — Central Processing Unit
Executes instructions. Must match socket, generation, and firmware.
DB9 — D-sub 9-pin serial connector
Legacy serial port still used for some consoles and industrial gear.
DDoS — Distributed Denial of Service
Many systems flood a target so legitimate users cannot get through.
DDR — Double Data Rate
SDRAM family. Modules of different generations are not interchangeable.
DHCP — Dynamic Host Configuration Protocol
Hands out IP, mask, gateway, and DNS automatically.
DIMM — Dual In-line Memory Module
Desktop RAM stick form factor.
DKIM — DomainKeys Identified Mail
Cryptographic signature that helps prove a message really came from the domain.
DLP — Data Loss Prevention
Controls that stop sensitive data from leaving approved channels.
DMARC — Domain-based Message Authentication, Reporting, and Conformance
Policy that tells receivers how to handle mail that fails SPF/DKIM.
DNS — Domain Name System
Maps names to records. If IP works and names fail, think DNS first.
DoS — Denial of Service
An attack that makes a service unavailable.
DRM — Digital Rights Management
Technical controls that restrict copying or use of licensed content.
DSL — Digital Subscriber Line
Internet over telephone copper. Distance from the CO matters.
DVI — Digital Visual Interface
Video connector that may be digital, analog, or both depending on the variant.
ECC — Error-correcting code
RAM that can detect and correct some memory errors. Common on servers.
EDR — Endpoint Detection and Response
Endpoint security that records activity and helps hunt/respond, not just signature-scan.
EFS — Encrypting File System
NTFS per-file/folder encryption tied to a user certificate.
EOL — End-of-life
Vendor no longer supports the product. Unpatched by definition going forward.
eSATA — External SATA
SATA brought outside the case. Largely replaced by USB and NVMe enclosures.
ESD — Electrostatic discharge
Static shock that can damage components silently. Strap, mat, and handling matter.
EULA — End-user license agreement
Contract that defines how software may be used.
exFAT — Extensible File Allocation Table
Filesystem for large flash media that both Windows and macOS speak well.
FAT32 — 32-bit File Allocation Table
Legacy filesystem with a 4 GB file-size limit.
FRT — Facial Recognition Technology
Biometric factor used by phones and Windows Hello-style sign-in.
FTP — File Transfer Protocol
Cleartext file transfer on ports 20/21.
GFS — Grandfather-Father-Son
Backup rotation using daily, weekly, and monthly media sets.
GPS — Global Positioning System
Satellite location service used by mobile devices.
GPT — GUID Partition Table
Modern partition scheme required for large disks and UEFI installs.
GPU — Graphics Processing Unit
Renders video. May be integrated or a discrete card with its own VRAM and power plugs.
GUID — Globally Unique Identifier
128-bit identifier used in GPT, AD objects, and many apps.
HDD — Hard Disk Drive
Spinning magnetic storage. Clicking is a replace-and-restore event, not a tweak.
HDMI — High-Definition Multimedia Interface
Digital audio/video cable common on displays and TVs.
HSM — Hardware Security Module
Dedicated crypto device for keys. Related to, but not the same as, TPM.
HTTP — Hypertext Transfer Protocol
Web protocol on TCP 80.
HTTPS — HTTP Secure
HTTP over TLS on TCP 443.
IaaS — Infrastructure as a Service
Cloud provider rents VMs, storage, and networks. You still patch the OS.
IAM — Identity and Access Management
Who a user is and what they may do across systems.
IMAP — Internet Message Access Protocol
Keeps mail on the server for multi-device access. Port 143.
IOPS — Input/Output Operations Per Second
Storage performance measure. Collapsing IOPS is a drive/RAID clue.
IoT — Internet of Things
Embedded devices on the network — cameras, sensors, printers with apps.
IP — Internet Protocol
Addressing and routing layer. IPv4 and IPv6 are both in A+ scope.
IPS — In-plane Switching
LCD panel type with strong color and viewing angles.
ISO — International Organization for Standardization / disk image
In A+ you will meet ISO files as bootable install images more often than the standards body.
ITX — Information Technology eXtended
Small motherboard family (Mini-ITX is the common A+ size).
KVM — Keyboard-Video-Mouse
Switch that shares input/display across multiple computers.
LAN — Local Area Network
Network in one building or campus.
LC — Lucent Connector
Small square fiber connector, very common in datacenters.
LCD — Liquid Crystal Display
Backlit panel family that includes IPS, TN, and VA.
LDAP — Lightweight Directory Access Protocol
Directory access protocol on port 389. AD uses it.
LED — Light-emitting Diode
Used in backlights, status lights, and Mini-LED displays.
LTE — Long-Term Evolution
4G cellular technology.
MAC — Media Access Control
48-bit hardware address on a NIC. Not the same as macOS.
MAN — Metropolitan Area Network
Network spanning a city.
MBR — Master Boot Record
Legacy partition table with a 2 TB practical limit.
MDM — Mobile Device Management
Policies, apps, wipe, and inventory for phones and tablets.
MDR — Managed Detection and Response
A vendor watches your telemetry and helps respond.
MFA — Multifactor Authentication
More than one factor: something you know, have, or are.
MFP — Multifunction Printer
Print, scan, copy, sometimes fax, in one device.
MMC — Microsoft Management Console
Host for snap-ins such as Event Viewer and Disk Management.
MNDA — Mutual Non-disclosure Agreement
Two-way confidentiality contract.
mSATA — Mini-SATA
Older small SSD form factor, largely replaced by M.2.
MSDS — Material Safety Data Sheet
Now often SDS. Tells you how to handle and dispose of chemicals such as toner.
MX — Mail Exchange
DNS record that names a domain's mail servers.
NAC — Network Access Control
Admits devices only after they meet policy (posture, identity).
NDA — Non-disclosure Agreement
Legal duty not to share confidential information.
NetBIOS — Network Basic Input/Output System
Legacy Windows naming/session API, often over ports 137–139.
NFC — Near-field Communication
Very short-range radio for tap-to-pay, pairing, and badges.
NIC — Network Interface Card
The adapter that puts a device on Ethernet or Wi-Fi.
NTFS — New Technology File System
Windows filesystem with permissions, encryption, and large volumes.
NTP — Network Time Protocol
Keeps clocks honest. Kerberos and logs depend on it.
NVMe — Non-volatile Memory Express
High-speed SSD protocol over PCIe, often in M.2 form.
OLED — Organic Light-emitting Diode
Self-emissive display. Perfect blacks, burn-in risk on static UI.
ONT — Optical Network Terminal
Fiber ISP device that converts light to Ethernet for the customer.
OS — Operating System
Software that manages hardware and applications.
OTP — One-time Password
Code valid once (or briefly). TOTP is the time-based variant.
PaaS — Platform as a Service
Provider manages OS/runtime; you deploy the app.
PAM — Privileged Access Management
Controls standing admin rights, often with just-in-time elevation.
PAN — Personal Area Network
Body/desk range — Bluetooth headset to phone is a PAN.
PCI — Peripheral Component Interconnect
Legacy expansion bus. Do not confuse with PCIe.
PCIe — PCI Express
High-speed serial expansion used by GPUs, NVMe, and NICs.
PCL — Printer Command Language
Common printer page-description language, contrasted with PostScript.
PII — Personally Identifiable Information
Data that identifies a person. Handle under policy, not convenience.
PIN — Personal Identification Number
Knowledge factor, often device-local (Windows Hello PIN is not the Microsoft password).
PIV — Personal Identity Verification
US government smart-card standard for identity.
PoE — Power over Ethernet
Power plus data on the same Ethernet cable. Injector or PoE switch required.
POP3 — Post Office Protocol v3
Downloads mail to one client. Port 110.
POST — Power-on Self-test
Firmware checks hardware before boot. Beep patterns are clues.
PSU — Power Supply Unit
Converts AC to DC rails. Wattage, connectors, and region voltage all matter.
PUP — Potentially Unwanted Program
Software the user may have accepted but that behaves like adware/crapware.
PXE — Preboot Execution Environment
Boot from the network to install or image an OS.
QoS — Quality of Service
Prioritizes traffic such as VoIP over bulk transfers.
RADIUS — Remote Authentication Dial-in User Service
Central authentication, common for enterprise Wi-Fi.
RAID — Redundant Array of Independent Disks
Combines disks for performance and/or redundancy. Not a backup.
RAM — Random-access Memory
Volatile working memory. Contents vanish when power is gone.
RDP — Remote Desktop Protocol
Windows remote GUI on TCP 3389.
ReFS — Resilient File System
Microsoft filesystem aimed at resiliency, seen on some Windows SKUs/workloads.
RFID — Radio-frequency Identification
Tags and badges read over a short radio range, longer than NFC typically.
RJ11 — Registered Jack 11
Telephone connector, narrower than RJ45.
RJ45 — Registered Jack 45
8P8C Ethernet connector.
RMM — Remote Monitoring and Management
MSP-style agent for inventory, patching, and remote control.
RSR — Rapid Security Response
Apple's out-of-band security patches between full macOS updates.
SaaS — Software as a Service
Provider runs the app. You use it in a browser or client. Email and docs suites are typical.
SAML — Security Assertion Markup Language
Federation protocol used for SSO between identity providers and apps.
SAN — Storage Area Network
Network dedicated to block storage.
SAS — Serial Attached SCSI
Enterprise disk interface. Different from SATA even when the connector looks related.
SATA — Serial ATA
Common HDD/SSD interface. Also a power connector shape.
SC — Subscriber Connector
Square fiber connector, push-pull.
SCADA — Supervisory Control and Data Acquisition
Industrial control systems. Treat them as legacy/embedded on A+.
SFTP — SSH File Transfer Protocol
File transfer inside SSH (port 22), not FTP.
SIM — Subscriber Identity Module
Identifies a cellular subscriber. eSIM is the soldered/programmable variant.
SLA — Service-level Agreement
Promised response/resolve times. Internal or third-party.
S.M.A.R.T. — Self-Monitoring, Analysis, and Reporting Technology
Drive health telemetry. A SMART failure is a replace-the-drive event.
SMB — Server Message Block
Windows file/printer sharing protocol on TCP 445.
SMS — Short Message Service
Text messages. Also an MFA channel, weaker than an authenticator app.
SMTP — Simple Mail Transfer Protocol
Sends email. Port 25.
SODIMM — Small Outline DIMM
Laptop RAM form factor.
SOHO — Small Office/Home Office
The small-network environment A+ tests constantly.
SOP — Standard Operating Procedure
Written repeatable process — imaging, onboarding, malware response.
SPF — Sender Policy Framework
DNS TXT policy listing servers allowed to send mail for a domain.
SPICE — Simple Protocol for Independent Computing Environments
Open remote-display protocol used by some virtualization stacks.
SQL — Structured Query Language
Database language. SQL injection is in A+ as a concept, not a coding exam.
SSD — Solid-state Drive
Flash storage. No seeking. Different failure modes than HDDs.
SSH — Secure Shell
Encrypted remote shell on TCP 22.
SSID — Service Set Identifier
The Wi-Fi network name. Hiding it is not a security control.
SSO — Single Sign-on
One authentication event unlocks many apps.
ST — Straight Tip
Round bayonet fiber connector.
TACACS+ — Terminal Access Controller Access-Control System
Cisco-associated AAA protocol, often for device administration.
TCP — Transmission Control Protocol
Reliable, ordered, connection-oriented transport.
TKIP — Temporal Key Integrity Protocol
Legacy WPA encryption. Prefer AES. Know it so you can recognize a weak AP.
TN — Twisted Nematic
Fast, cheap LCD with poor viewing angles and color.
TOTP — Time-based One-time Password
Authenticator-app codes that rotate with the clock.
TPM — Trusted Platform Module
On-board crypto chip. BitLocker and Windows 11 hardware requirements use it.
UAC — User Account Control
Windows prompt that separates standard and admin tokens.
UDP — User Datagram Protocol
Connectionless transport. Fast, no built-in reliability. DHCP and many real-time apps use it.
UEFI — Unified Extensible Firmware Interface
Modern firmware replacing BIOS. Secure Boot lives here.
UPnP — Universal Plug and Play
Lets LAN devices open router ports automatically. Convenient and risky.
UPS — Uninterruptible Power Supply
Battery backup for brownouts and blackouts. Not the same as a surge strip.
USB — Universal Serial Bus
Family of connectors and speeds. USB-C is a connector shape, not automatically a speed.
UTM — Unified Threat Management
Appliance combining firewall, IPS, AV, and related services.
VA — Vertical Alignment
LCD type with strong contrast, moderate angles.
VDI — Virtual Desktop Infrastructure
Desktop OS runs in the datacenter; the user sees a remote session.
VGA — Video Graphics Array
Analog 15-pin video. No native audio. Easy to bend pins.
VLAN — Virtual LAN
Logical broadcast domain on a switch. Isolation without extra cables.
VM — Virtual Machine
Guest OS on a hypervisor.
VNC — Virtual Network Computing
Cross-platform remote framebuffer. Encrypt it or tunnel it.
VoIP — Voice over IP
Phone audio on the data network. Jitter and latency ruin it.
VPN — Virtual Private Network
Encrypted tunnel across an untrusted network.
VRAM — Video RAM
Memory on a GPU. Apps can require a minimum.
WAN — Wide Area Network
Network over long distance — typically the ISP link.
WAP — Wireless Access Point
Another name for AP.
WinRM — Windows Remote Management
Windows remote management protocol used by PowerShell remoting.
WISP — Wireless Internet Service Provider
Fixed wireless ISP. Useful when cable/fiber/cellular are missing.
WLAN — Wireless LAN
Wi-Fi network.
WPA — Wi-Fi Protected Access
Wi-Fi security family. A+ current scope emphasizes WPA2 and WPA3.
WWAN — Wireless Wide Area Network
Cellular data network from a PC's point of view.
XDR — Extended Detection and Response
Detection/response across email, identity, cloud, and endpoints — broader than EDR.
XFS — XFS filesystem
High-performance Linux filesystem listed in current A+ objectives.
XSS — Cross-site Scripting
Injecting script into a web app so another user's browser runs it.