# What is an e-cigarette: the term explained > What is an e-cigarette: the four parts, the words that mean the same thing, the device families and the UK limits, set out plainly for beginners. The word travels everywhere, across shop windows and conversations, and yet it covers objects that have almost nothing in common to look at: a slim tube, a flat box, a chassis covered in buttons. Asking **what is an e-cigarette** therefore has a real answer, but it is a technical one rather than a visual one. Before choosing anything at all, it is worth knowing which words cover which reality. ## What is an e-cigarette in one sentence An e-cigarette is an electronic device that heats a flavoured liquid, with or without nicotine, by means of a coil powered by a battery, in order to produce a vapour inhaled by an adult user. That definition holds four inseparable elements: a power source, a heating element, a reserve of liquid and a mouthpiece. Everything else, the size, the shape, the settings or the colour, is a variation on the same principle. Put another way, a flat pod the size of a card and a two hundred gram box belong to exactly the same technical category. They differ only in bulk, battery life and how much control is handed to the user. ## The four parts every device shares Whatever model you are looking at, the operation always rests on the same components. Knowing them lets you read a listing without getting lost and understand what a shop assistant is describing. Here are the four building blocks, in the order they come into play. **The battery** This is the power source. It is either built into the device and charged over a USB cable, or removable in the form of a cell you swap out. Capacity is quoted in milliamp hours, and a higher figure means longer between charges at comparable use. The battery section also houses the control electronics, called a chipset on adjustable models. That is what limits the power delivered and cuts the supply when something is wrong. **The coil** The consumable part above all others, a coil is a wire or a metal mesh wrapped in cotton, sitting in a small housing that screws or clips in. The cotton takes up liquid, the metal heats, the liquid turns to vapour. Its value is quoted in ohms. A high resistance coil, above 1 ohm, heats gently and suits a tight draw. A low value heats hard and produces more volume. **The tank or pod** The tank holds the liquid and keeps it in contact with the cotton in the coil. On a pod device, tank and coil are often a single replaceable part. On a conventional clearomiser the two separate. **The e-liquid** The liquid combines two carriers, propylene glycol and vegetable glycerine, food grade flavourings and, depending on the reference, nicotine. The ratio between the carriers determines how dense the vapour is and how sharply the flavour reads. ## E-cigarette, vape, pod: the words that mean the same family British vaping vocabulary grew faster than any standard for it. Several words coexist for a single object, and that accounts for a good share of the early confusion. E-cigarette, e-cig, electronic cigarette and vape are strictly interchangeable in everyday use. Personal vaporiser belongs to the more technical register of specialist forums. Pod, box, tube and kit, by contrast, are not synonyms but precise formats, which is to say subcategories. Official documents use another term again, electronic nicotine delivery system, shortened to ENDS, when the liquid contains nicotine. Holding on to that distinction avoids a common mix up: asking for a pod in a shop is not asking for an e-cigarette in general, it is asking for a compact format that takes a cartridge. ## What the rules fix in the United Kingdom The legal definition is narrower than the everyday one, and it puts hard figures on the hardware sold here. Those caps come from the Tobacco and Related Products Regulations, and they apply to every retailer in Britain. Three numbers are worth knowing. A refillable tank is capped at 2 ml. A bottle of nicotine containing liquid cannot exceed 10 ml. Nicotine strength is limited to 20 mg/ml. Sales to under 18s are prohibited, and single use disposables are no longer sold. Those boundaries explain design details that often surprise newcomers: the small pod capacity, and bottles that always arrive with a child resistant cap and a tamper evident ring. ## The main device families With the definition settled, the formats on the shelf still need placing. Three families cover very nearly the whole offer, and each corresponds to a different philosophy of use. Moving from one to the next is in no way compulsory. **The pod** A compact body, frequently with no button at all, fed by a prefilled or refillable cartridge. It is the easiest format to pick up, at the cost of a modest battery. **The pen or tube** A long silhouette, one button, a clearomiser screwed on. This older format offers a solid compromise between simplicity, battery life and how easily coils can be found. **The box** A screened body, adjustable power, often removable cells. A box speaks to people who want every parameter under control and accept a longer learning curve for it. ## What the definition leaves out: the draw No definition mentions the draw, and yet the draw drives most of what the device feels like. Two units identical on paper can deliver opposite experiences depending on how much air comes in. The tight draw, called MTL for mouth to lung, means pulling into the mouth first and inhaling afterwards. The airy draw, DL for direct lung, brings the vapour straight down with a far higher airflow. That parameter is set on the airflow ring, the perforated collar at the base of the tank. The vocabulary of early adjustment deserves a detour of its own, and our method for [vape wattage settings](/uk/vape-wattage-settings/) starts from exactly this pairing of coil and airflow. ## Frequently asked questions ### Is there a difference between an e-cigarette and a vape? None at all. The two words name the same object, one being simply the shorter, more current form. British shops use them interchangeably, often in the same sentence. ### Does the device always contain nicotine? No. The hardware is neutral, and it is the liquid that contains nicotine or does not. Nicotine free references exist across every flavour and work with exactly the same equipment. ### What does mAh mean on a listing? It states battery capacity in milliamp hours. At comparable use, a higher figure means more hours before the charger comes out again. ### How long does a coil last? Its working life is generally counted in weeks and depends heavily on the liquid, the power applied and how often the device is used. Heavily sweetened liquids clog the cotton considerably faster. ### Can I take one on a plane? Devices must travel in hand luggage and never in the hold, because of their lithium cells. The precise rules vary by airline and destination and are worth checking before every flight. ## What is an e-cigarette: the essentials to keep Asking **what is an e-cigarette** comes back to four things: a battery, a coil, a tank and a liquid. Every format on the British market, from a pocket pod to an adjustable box, applies that same scheme and varies only in bulk and in how much control it hands over. The vocabulary follows the same logic, a few synonyms for the object and a few precise words for the formats. Once that grammar is in place a listing becomes readable, the [criteria for choosing](/uk/how-to-choose-a-vape/) start to mean something, and [the first pod in your hand](/uk/how-to-use-a-pod-vape/) stops being a gamble. Editorial content written for adult readers in the United Kingdom. Vaping products commonly contain nicotine, which is addictive. Nothing here is a purchase recommendation, and these products are not sold to anyone under 18.