Tech Glossary: AI & Gadget Terms Explained
Marketing language in tech is designed to impress, not inform. This glossary defines the terms you'll see in reviews, product pages, and spec sheets — in plain English, with no jargon required to understand the jargon.
AI & Machine Learning
Artificial Intelligence (AI)
Software that performs tasks that typically require human judgement — recognising faces, understanding speech, recommending content. In consumer gadgets, "AI" usually means the device has a trained model running locally or in the cloud.
Machine Learning (ML)
A type of AI where a model improves through experience. Your smart thermostat "learning" your schedule is machine learning — it adjusts based on your behaviour patterns, not pre-programmed rules.
On-Device AI
AI processing that happens on the device itself rather than in the cloud. Faster (no internet needed), more private (data doesn't leave the device). Requires a dedicated AI chip (NPU). Found in flagship phones (Apple A18, Snapdragon 8 Gen 4) and smart home hubs.
Neural Processing Unit (NPU)
A chip inside phones and devices specifically designed to run AI calculations efficiently. Separate from the CPU and GPU. A phone with an NPU handles face unlock, real-time translation, and photo enhancement faster and with less battery drain than one without.
Large Language Model (LLM)
The AI behind chatbots like ChatGPT and Gemini. Trained on vast amounts of text, LLMs generate human-like responses. When a phone advertises "AI assistant" features, the on-device component is typically a compressed LLM.
Smartphones & Mobile
5G
The fifth generation of mobile networks. Significantly faster than 4G LTE for downloads; the main benefit in 2026 is more consistent speeds in crowded areas. Sub-6GHz 5G (wider coverage, moderate speed) vs mmWave 5G (short-range, very fast — mainly dense cities).
eSIM
An embedded SIM card built into the phone. You activate a carrier plan via QR code instead of a physical SIM card. Allows instant carrier switching and dual SIM without needing two SIM slots. See our full guide: eSIM vs Portable WiFi.
Refresh Rate (Hz)
How many times per second the screen updates. 60Hz is standard; 90Hz and 120Hz feel noticeably smoother for scrolling and gaming. ProMotion (Apple) and LTPO (most flagships) dynamically drop to 1Hz when the screen is static to save battery.
IP Rating (IP67, IP68)
Ingress Protection rating. The first digit (6) = dust resistance level (6 = fully dust-tight). The second digit (7 or 8) = water resistance depth. IP67 = 1 metre for 30 minutes. IP68 = 1.5+ metres for 30 minutes (exact depth varies by manufacturer).
SoC (System on a Chip)
The main processor that combines CPU, GPU, NPU, modem, and RAM controller on a single chip. Apple A18 (iPhone 16), Snapdragon 8 Elite (Android flagships), and Dimensity 9300 (mid-range flagships) are the leading 2026 SoCs.
Carrier Locked vs Unlocked
A locked phone only works with one carrier. An unlocked phone works with any carrier's SIM. Unlocked phones cost more upfront but save $300–$600 over 24 months via cheaper MVNO plans. See: Carrier Deals vs Unlocked.
Wearables
SpO2 (Blood Oxygen Sensor)
Measures the percentage of oxygen in your blood using light sensors on the watch back. Normal range is 95–100%. Useful for detecting sleep apnea and altitude sickness. Accuracy varies by device — Fitbit and Garmin outperform Apple Watch in continuous SpO2 monitoring based on 2025 peer-reviewed studies.
ECG (Electrocardiogram)
Records electrical activity of your heart. On a smartwatch, you place a finger on the crown/button to complete a circuit. Can detect atrial fibrillation (AFib). Apple Watch Series 4+ and Samsung Galaxy Watch 4+ have FDA-cleared ECG features.
Always-On Display (AOD)
Screen that stays partially lit to show time and key data without raising your wrist. Cuts battery life by 30–50%. On LTPO displays, AOD runs at 1Hz (one update per second) to minimise drain.
Smart Home
Matter Protocol
The universal smart home standard backed by Apple, Google, Amazon, and Samsung. A Matter-certified device works with any smart home ecosystem. Eliminates the "works with Alexa but not HomeKit" problem. Most 2024+ smart home devices are Matter compatible.
Thread
A low-power mesh networking protocol for smart home devices. Unlike Wi-Fi, Thread devices communicate directly with each other (mesh) rather than routing through a central hub. Faster response, more reliable, lower battery drain for battery-powered sensors.
Zigbee / Z-Wave
Older mesh protocols still used by many smart home devices. Zigbee is more common (Philips Hue, SmartThings). Z-Wave has longer range. Both require a hub. Being gradually replaced by Matter + Thread in 2025–2026.
Local vs Cloud Processing
Local processing happens on-device or on a local hub — no internet required, faster response, more private. Cloud processing sends data to a server — requires internet, may have latency, vendor controls your data. For security cameras and smart locks, local processing is strongly preferred.
Audio & Earbuds
ANC (Active Noise Cancellation)
Microphones on the earbuds pick up ambient noise; the device generates an inverse sound wave to cancel it out. Effective for consistent low-frequency noise (planes, trains, office HVAC). Less effective for sudden or high-frequency sounds.
Codec (SBC, AAC, aptX, LDAC)
The format used to compress and transmit audio wirelessly. SBC is the baseline (every Bluetooth device). AAC is Apple's standard (good quality). aptX and aptX HD (Qualcomm) offer better quality on compatible Android devices. LDAC (Sony) transmits 3x more data than SBC at 990kbps — highest quality when both devices support it.
Transparency Mode
Uses ANC microphones in reverse — passes external sound through to your ears so you can hear announcements or conversations without removing the earbuds. Quality varies: Apple AirPods Pro leads for natural transparency; Sony WF-1000XM5 is a close second.
This glossary is updated quarterly. Last updated: June 2026.
For full product comparisons, see our review guides.