£sd

£sd (occasionally written Lsd) is the popular name for the pre-decimal currencies once common throughout Europe. The abbreviation originates from the Latin currency denominations librae, solidi, and denarii. Under this system, there were 12 denarii in a solidus and 20 solidi (or 240 denarii) in a libra. In the countries of the (former) British Empire, these were called pounds, shillings, and pence (pence being the plural of penny), with 12 pence in a shilling and 20 shillings in a pound.

Although the names originated from popular coins in the classical Roman Empire, their definitions and the ratios between them were introduced and imposed across Western Europe by Emperor Charlemagne. King Offa of Mercia adopted the Frankish silver standard of librae, solidi, and denarii into Britain in the late 8th century.

The £sd system was the standard across much of the European continent for over a thousand years, until the decimalisations of the 18th and 19th centuries. The United Kingdom remained one of the few countries retaining it into the 20th century, resulting in the system becoming particularly associated with Britain. For much of the 20th century, £sd remained the monetary notation of most countries in the (former) British Empire – with the exceptions of Canada and India – until the 1960s and 1970s, with Nigeria being the last to abandon it in the form of the Nigerian pound on 1 January 1973.

Historically, similar systems based on Roman coinage were used elsewhere; e.g., the division of the livre tournois in France and other pre-decimal currencies such as Spain, which had 20 maravedís to 1 real and 20 reales to 1 duro or 5 pesetas.