The word clog, as applied to footwear, has these meanings:

1. A type of shoe or sandal made predominantly out of wood.
2. A type of heavy boot or shoe with leather sides and uppers and typically thick wooden soles. They may have steel toecaps and/or steel reinforcing inserts in the undersides of the soles.
3. A special kind of shoe worn while clog-dancing (clogging). They are similar to tap shoes, but the taps are free to click against each other, therefore producing a different sound than tap shoes.
4. Nowadays, "clogs" also means comfortable slip-on shoes. They are often made out of leather, but some clogs keep the bottom part out of wood. All-rubber clogs are often worn while gardening, because they can be easily hosed off and allowed to air-dry. Some clogs come with heels, and are usually distinguished from mules by their higher vamp. It is commonly accepted that men and women can wear low-heeled or high-heeled clogs.Fact: date=May 2007

Clogs (with meaning 1 or 2) were, and in some regions still are, widely worn by workers as protective clothing in factories, mines and farms.

Traditional clogs in Europe

Traditional clogs are made out of many different species of wood (willow, poplar, birch, beech, alder wood). They are associated with the Netherlands, Belgium, Denmark and Sweden (though Swedish clogs do not resemble Dutch clogs) as part of the touristic "Holland"/Sweden image, where they are seen as a form of national dress. Because of this, Dutch people are sometimes called cloggies, that is, clog-wearers. In Dutch, clogs are known as klompen. The traditional, all wooden clogs have been officially labelled as safety shoes, passing European standards for the CE mark with flying colours. Today, Dutch clogs are available in many tourist shops. Wearing clogs is considered to be healthy for the feet. Despite that fact, the Dutch don't use them much anymore for everyday use, but clogs are still used by people working in their gardens, farms, and by planters.

In England slats of wood held in place by thonging or similar were known as "Pattens" and they were usually worn over leather or fabric shoes to raise the wearer's foot above the mud of the unmade road. Poorer people who couldn't afford shoes wore wood directly against the skin, and so the clog was developed, made of part leather and part wood. The English tended to carve Welsh and West Country alder, Scottish birch and Lincolnshire willow. The Welsh used alder, birch & sycamore. The wearing of clogs in Britain really took off with the Industrial Revolution, when workers in the mills, mines, iron, steel, and chemical works, workshops and factories needed strong, cheap footwear. The heyday of the clog in Britain was between 1840s and 1920s and, although traditionally associated with Lancashire, they were worn all over the country, not just in the industrial North of England. There is a theory that clogging or clog dancing arose in these mills as a result of the mill workers entertaining themselves by syncopating foot taps with the rhythmic sounds made by the loom shuttles. Clog dancing became a widespread pastime during this period in England. During the nineteenth century, competitions were held and there were professional clog dancers who performed in the music halls.