The Great British Freeze - a user's guide So, winter draws on, as the old comedians used to nudge-nudgingly say. And indeed it does, what with -18.3C overnight in Chesham, Buckinghamshire, -15.6C in Holbeach, Lincolnshire, -11C in Charnwood, Surrey, and -10C widely experienced across Cambridgeshire, Oxfordshire and Bedfordshire. Scotland, which normally takes the brunt of these things, and Northern Ireland were the milder exceptions. Weather experts - from seaweed users to the more scientific type - seem at odds as to how long this most seasonable of Februaries will last. A bit of mildness on Monday and Tuesday may last. It may not. But the confusion is not confined to them. Already during this winter the unversed have been bombarded with not only a lot of chilly elements, but also some unfamiliar terms. So here, by way of assistance, is The Independent on Sunday glossary so you can bluff your way through the rest of this winter: Blizzard Used by most of us to describe anything heavier than just a few flakes falling, as in "I can't come to work today, it's a blizzard out there." In the US, where the word was first applied to a mixture of heavy snow and strong winds in the 1870s, it requires a wind speed of at least 35mph. No such pernicketiness here. Glaze Correct term for the result of rain freezing on impact with anything it touches. Can fatally immobilise birds, and it also creates perhaps the most lethal road conditions, making it difficult for even an agile adult to walk without falling, let alone a car to stop skidding. Sometimes called black ice. Frost hollow Area of low ground, invariably in a valley, where temperatures can be many degrees colder than surrounding land. Common in Scottish glens and along Welsh borders, they can occur elsewhere. Famous ones are at Rickmansworth, Hertfordshire, and Chipstead Valley in Surrey. Hoar frost Winter equivalent of dew. Happens when moist air comes into contact with vegetation which is below freezing and colder than surrounding air. Ice crystals, often of considerable size and beauty, then form on leaves and branches, sometimes so thickly it looks like snowfall. Sleet Not a word used by meteorological purists, it is a mixture of rain and part-melted snow more often called "wintry showers" by weather forecasters. Best thought of as precipitation that can't make up its mind whether it's rain or snow. Aerial slush, really. Freezing fog Commonly used when it's a) cold and b) foggy. In fact, it is either when water vapour is sufficiently cold to produce ice crystals similar to light snow, or when water vapour in fog freezes on surfaces and so coats them with frost. Snow White, six-pointed flakes, each one famously unique, and very light because of the space between the water molecules. Depth in one's area is ritually exaggerated by duvet-lovers, as in "There's four inches here - I can't get in today." See Blizzard, above. Brrr... Tabloid headline prefix, as in "It's Brr... Brrritain. Archaic, which doesn't stop it being frequently used. Other journalistic weather terms include "It's Chaos!" (used to describe winter transport conditions when a tabloid editor's journey to London office has been incommoded); and "Britain paralysed!" (headline update when editor has been inconvenienced on way home as well).