The 2000 presidential election descended into farce

The term "chad" - the tiny piece of paper punched out of a ballot when a vote is cast - became common currency in the aftermath of the election.

In the tight race for votes in Florida, the question of what really counts as a vote - a clear hole in a ballot paper, or a bulge? - was hotly debated.

Voters were supposed to use a pointed instrument to knock out the small rectangles alongside their choice of candidate.

But tens of thousands of ballot papers in Florida were discarded by the automatic counters because they were not properly punched through.

Fierce arguments ensued about whether to count ballots whose chads had managed to cling on by one or more of the cardboard slivers connecting it to the card.

Pregnant chad - also known as dimpled chad or nipple chad . This is where the paper bulges out but has not been pierced:

- also known as or . This is where the paper bulges out but has not been pierced: Hanging chad - where the little bit of paper is attached to the ballot by one corner. Swing-door chad - or swinging chad. The little piece of paper is attached to the ballot by two corners

- where the little bit of paper is attached to the ballot by one corner. Slit chad - where the chad has only been perforated on one side, but enough to allow a chink of light through.

- where the chad has only been perforated on one side, but enough to allow a chink of light through. Tri chad - where the paper is attached to the ballot by three corners, but one corner is free.

The debate went all the way to the US Supreme Court. Numerous allegations about tampering with chads circulated, including the bizarre accusation that a Democrat had eaten chads.

The origins of the word are unclear, but it first appeared during the early days of telegraphy and computing.

It may also come from the Scottish word for gravel, or riverbed stones.

Another idea is that the word came from America, from the Chadless Keypunch, named after its inventor. The card punch cut little U-shapes in cards, rather than punching out a circle or rectangle.

Since the serrations were "chadless", the circles left by other punches must be "chads", went the reasoning.