Country in west Africa, bordering Guinea-Bissau, Senegal, Mali, Cote d'Ivoire, Liberia and Sierra Leone. The word seems to have been a general name for that coastal area, since two other countries (Guinea-Bissau and Equatorial Guinea) use it in their names.

The guinea was also a British coin, minted of gold imported from West Africa and originally issued in 1663 as equal to one pound or twenty shillings. It was the first British coin to be manufactured by machine ther than hand-hammered. The coins had an elephant stamped on them, and on the edges inscribed "Decus et Tutamen" (ornament and safeguard, which was the purpose of the inscription, an anti-clipping measure). However, the value of the gold in the nearly 8-gram coin increased beyond the face value of the coin; by June 1695 they were trading at 30 shillings. People sold gold for silver and then exported the silver out of the country to make a profit. The government tried to bring down its price by refusing to accept it for tax payments at a value of more than 22 shillings. In 1699, there was a further reduction to 21.5 shillings (21 shillings 6 pence) and in 1717 to 21 shillings, which continued to be its value as long as the coin was issued. This did reduce the export of silver some, but not as much as had been hoped.

The guinea coin was minted until 1821, when a new coin worth exactly a pound, the sovereign was introduced under George IV. However, expensive items were still priced in guineas as a gesture of wealth until at least 1969 when Britain abandoned the shilling entirely, moving to a decimal currency system of just pounds and pence.

Source: Bernstein, Peter L. The Power of Gold: The History of an Obsession. New York: John Wiley & Sons, 2000.