Security and smart home marketing leans heavily on jargon, and some of it is deliberately opaque. This page defines the terms you will actually encounter, in the order you would meet them alphabetically.
Where a term deserves more than a definition, we have linked to the guide that covers it properly.
A to Z
A lock security rating from the American National Standards Institute. Grade 1 is the highest residential rating and survives the toughest forced-entry and cycle testing; Grade 3 is basic. Most smart locks are Grade 2; only a few are Grade 1.
Away arms every sensor including interior motion. Home arms the perimeter but not interior motion, so you can move around. Night is typically perimeter plus selected interior zones. Choosing the wrong mode is the most common cause of self-inflicted false alarms.
The hub of a security system. It communicates with sensors, decides when to trigger, and contacts the monitoring centre. Should have battery backup and a cellular radio so cutting power and broadband does not silence it.
A mains-powered device connecting a Thread mesh to your home network. A HomePod mini, Nest Hub or newer Echo usually serves as one. Without it, Thread devices cannot reach the internet.
A mobile radio in the base station that reports alarms when broadband is down or the router has been unplugged. Usually a few dollars a month and the single most worthwhile monitoring upgrade.
A wire supplying continuous low-voltage power to a thermostat. Many older US homes lack one. Smart thermostats generally need it; ecobee includes a Power Extender Kit that works around its absence.
The facility where professional monitoring operators work. When an alarm triggers, an operator here calls you and dispatches police if needed. Quality varies with redundancy and staffing.
Networks broadcasting on both 2.4 GHz and 5 GHz. Many smart devices only support 2.4 GHz, which is why setup fails on a combined network — you may need to separate the bands temporarily.
The grace period between opening a door and the alarm sounding, letting you disarm. Too short causes false alarms; too long lets an intruder find the panel. Thirty to sixty seconds suits most homes.
A charge levied by many municipalities for police dispatch to false alarms — commonly $50–$150 after the first one or two, escalating with repeats. Some areas also require a paid alarm permit.
Using your phone’s location to trigger actions when you enter or leave an area — arming as you leave, unlocking as you arrive. Reliability depends on phone battery settings and needs tuning.
Eufy’s local storage hub. Cameras record to it rather than the cloud, removing subscription costs. Its weakness is being a single point of failure: if it is stolen, the footage goes with it.
Ingress protection. Two digits: dust then water. IP65 is the practical minimum for an unsheltered outdoor camera; IP66 for walls facing driving rain. Says nothing about UV or temperature resistance.
Recording video to a device in your home — a microSD card, a hub, or an NVR — rather than to a company’s servers. Removes subscription cost and keeps working offline, but is vulnerable to theft.
A common language for smart home devices, backed by Apple, Google, Amazon and Samsung. Delivers reliable basic control across ecosystems; advanced features usually remain in the manufacturer’s own app. See our explainer.
Passive infrared sensor detecting body heat moving across its field of view. Prone to false triggers from radiators, sunlit windows and air vents. Pet-immune versions ignore animals below a weight threshold.
Network or digital video recorder — a box storing footage from multiple cameras locally. The professional approach to local storage, common with PoE camera systems.
Software distinguishing people from cars, animals and moving branches. The single most important feature for reducing useless notifications. Runs either on the device (fast, works offline) or in the cloud.
Delivering power and data to a camera over one Ethernet cable. The most reliable way to run cameras: no batteries, no Wi-Fi congestion. Requires cable to each camera, so it is usually professional work.
A paid service where a central station responds to alarms and dispatches emergency services. Typically $10–$70 a month. The alternative is self-monitoring, where you receive a notification and decide.
A platform passing alarm data directly into emergency dispatch systems, shortening the handoff between monitoring centre and responders. Supported by several security brands.
Receiving alerts yourself instead of paying a central station. Free, and genuinely adequate for many households — weaker if you travel, sleep heavily, or are often unreachable.
A low-power mesh network for smart home devices. Mains-powered devices relay for battery ones, so coverage improves as you add devices. Requires a border router.
A speaker and microphone in a camera or doorbell, letting you speak to whoever is there. Genuinely useful for deliveries and as a deterrent.
An alarm confirmed as genuine by a human or by video before dispatch. Matters because many police jurisdictions deprioritise unverified alarms given high false-alarm rates.
A sub-GHz mesh protocol for smart home devices. Avoids the congested 2.4 GHz band, so it penetrates walls better than Thread or Zigbee. Strong certification programme means reliable interoperability.
A 2.4 GHz mesh protocol with a very large installed base — Philips Hue runs on it. Cheap and widespread, but competes with Wi-Fi for airtime.
Terms that mean less than they suggest
A few pieces of vocabulary appear constantly in marketing and carry little real meaning. Worth recognising.
“Military-grade encryption.” Almost always means AES-256, which is the ordinary standard used by every bank, browser and messaging app. It is not a differentiator.
“AI-powered.” Usually means person detection, which nearly every camera has had for years. Ask specifically whether detection runs on the device or in the cloud — that difference is real and affects speed and offline behaviour.
“Professional-grade.” Has no defined meaning in consumer security. For locks, ask for the ANSI grade. For outdoor equipment, ask for the IP rating.
“No contract” with financed equipment. Technically accurate and practically misleading — a 60-month equipment financing agreement carries obligations very similar to a contract.
“Free installation.” Frequently recovered through a longer monitoring commitment. Ask what the total is across the full term.
Frequently asked questions
What is a C-wire and do I need one?
A wire supplying continuous power to a thermostat. Most smart thermostats need one; ecobee includes a Power Extender Kit for homes without. Photograph your thermostat wiring to check.
What does IP65 mean on a camera?
Dust-tight, and protected against low-pressure water jets. It is the practical minimum for an unsheltered outdoor camera. IP66 is better for walls facing driving rain.
What is a verified alarm?
An alarm confirmed as genuine by a human or video before police are dispatched. It matters because many jurisdictions deprioritise unverified alarms.
Is "military-grade encryption" meaningful?
No. It almost always means AES-256, the ordinary standard used by every bank and browser. It is marketing, not a differentiator.