TV jargon buster

By Mike Atherton 17 Dec 2017

With all the new technology that's being introduced to the world of TVs, it can be difficult to keep up with what all the acronyms stand for - and more importantly, what they actually mean. 

So if you're not sure what the difference between LED and LCD is, or if you want to know what 4K actually means, this guide should help make things a little clearer. 

Refresh rates (processing rates)


TV refresh rates are usually measured in 'Hz' and are also known as 'processing rates'. It refers to rate that the image refreshes itself and generally speaking, a higher rate means you'll get a better, more stable picture. Some manufacturers use their own image quality rating system, like Samsung's PQI (Picture Quality Index), which also takes things like contrast, colour, and motion blur into account.

When considering refresh rates, it's worth noting that TV broadcasts, DVDs and even Blu-ray movies, are not played at a rate higher than 60Hz. Higher refresh rates usually mean you'll see less motion blur on fast moving images, so if you watch a lot of sport or you're planning on using the TV for gaming, it's worth looking for one with a rating of 120Hz or higher.

HD, Full HD & Ultra HD


These are all about the picture quality, and they refer to the number of pixels that have been packed into the screen - the more pixels, the better the picture.

Standard HD will give you 720 vertical pixels, and 1280 horizontal, while Full HD gives you 1080 x 1920. Then there's a huge jump to Ultra HD (or 4K), which gives you 2160 x 3840 pixels - that’s a total of 8 million pixels producing the highest quality images currently available.

While 4K TV's are able to produce a very impressive picture quality, manufacturers aren't stopping there, with many leading brands already planning releases of 8K TVs in the next couple of years.



3D TV has been around for a few years now and many LED TVs now come with a free set of 3D glasses. There are two different types of 3D technology - 'active', or 'passive'. 

Active 3D

With active 3D, each lens on the glasses flickers at a very high rate, in sync with the image on the TV screen. This means that the TV can send a different image to each eye to create that 3D effect.

Passive 3D

If you've ever watched a 3D movie at the cinema, this will likely have used 'passive' technology. It uses a filter on the screen which, when viewed with the 3D glasses, lets you see half of the pixels with one eye and the other half with the other eye. This approach does mean that you'll lose some of the resolution because you'll only be seeing half of the available pixels, so the picture won't look as sharp. 

Aspect ratio


This describes the height and width of the image you see on the screen. Most TV shows these days are presented at the 16:9 ratio, which is the standard widescreen picture that most of us are familiar with. The reason we've now settled on this ratio for most of our TV viewing is that this is the ratio that most closely replicates our field of view.

If you're watching an older TV show or movie, you might see it in 4: 3, which means you'll see a more squared off picture, with a thick black bar down each side of the image.

The ratio can also go the other way, with lots of movies filmed in 2.39:1, which is why you'll often see black bars above and below the picture. 

Mike Atherton

If you want to get rid of these bars, your TV will have an option to zoom into the image to fill the screen – but this does mean you'll lose some of the picture at the sides.



These describe the type of screen technology that's used in the TV. Most flat-screen TVs currently use both LED and LCD panels to produce a picture. The LED (Light Emitting Diode) is the backlight that sits behind the LCD (Liquid Crystal Display) panel, and the TV creates pictures and colour by opening and closing the pixels on the LCD panel to let light through.

OLED TVs are a relatively new technology and they work a little differently to LED and LCD. It stands for Organic LED, and does away with the backlight altogether. Instead, each pixel has its own power source which means it can be switch on and off independently, creating deeper blacks and better contrast ratios.

Find out more about OLED TVs here.

Contrast ratio


The contrast ratio tells you how well the TV can display the brightest whites, compared to the darkest black, while still maintaining a high level of detail. It sounds straight forward but different manufacturers often measure this in different ways, so it can get a little confusing.

The two main ways that manufacturers display this information is by showing the 'dynamic ratio', and the 'static ratio' (also known as the native ratio). The static ratio is generally the more reliable number, but because manufacturers tend to measure the ratios differently, we'd recommend only comparing the contrast ratio between TVs of the same manufacturer.

Freeview & Freesat


Most people in the UK have heard of Freeview – it's the digital TV service that's supplied through your TV aerial, and all new TVs should be able to receive Freeview channels. You just need to connect your TV to an indoor or outdoor aerial - bear in mind though, that the number of channels you receive can depend on the signal strength, so indoor aerials aren't always the best option.

Freesat is similar to Freeview but as the name suggests, there's no subscription fee, and it uses a satellite dish instead of an aerial. To be able to receive Freesat, you'll need a separate 'Freesat box' connected to your TV. One of the benefits of Freesat is that it's available anywhere in the UK, so if you struggle to get a good signal with your standard TV aerial, Freesat might be a good alternative.



HDMI stands for High-Definition Multimedia Interface, and it's how most of our kit is connected to our TVs. It carries high-quality video and audio signals to your TV from all sorts of things like DVD players, set-top boxes, and games consoles.

Optical output


You might have noticed the optical output on the back of your TV but never been sure what it's for. It's the small square shaped socket, and it's used for connecting things like sound bars, or home cinema kits to your TV.

Optical cables work differently to most TV cables because they use fiber optic light to send signals from your TV to whatever they're connected to. Optical cables can support anything up to a 5.1 surround sound system, but if you have anything bigger than that, you'd probably be best using HDMI.



SCART is an older type of connection which has now been almost entirely replaced by the digital HDMI connector. You'll still find a SCART socket on some TVs, but most manufacturers have done away with them altogether.

Smart TV


A smart TV is any TV that connects to the internet to use online services - this could be anything from playing games to streaming movies, or just browsing the web.

Take a look at our what is a smart TV article to find out more about what they can do.



USB connectors can be found in lots of different devices, and come in many shapes and sizes, but the most common is the 'USB A' – this is what you'll find on most PCs, laptops, games consoles, and TVs. 

Their main function is to transfer data from one device to another, so if your TV has a USB port, you'll be able to plug in a memory stick to play movies or show family photos on your TV.

TV on-demand


On-demand TV describes any online catch-up TV service like BBC iPlayer, Channel 4's All 4, or UKTV Play. Most of these 'catch-up' services are free, but you can also pay a subscription fee to get access to vast TV and movie libraries from services like Netflix and Amazon Video.

To be able to use any of these services, you'll need to be able to download the app to a smart TV, streaming stick, set-top box, or games console. Most of them are also available on smartphones and tablets.

If you don't have a smart TV, our guide to streaming on a non-smart TV will give you some helpful alternatives.

Hopefully, all that jargon makes a little more sense now, but if there's anything else that you need help with, you can contact one of our Team Knowhow experts here.

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