The full official name pound sterling (plural: pounds sterling), is used mainly in formal contexts and also when it is necessary to distinguish the United Kingdom currency from other currencies with the same name. Otherwise the term pound is normally used. The currency name is sometimes abbreviated to just sterling, particularly in the wholesale financial markets, but not when referring to specific amounts; for example, "Payment is accepted in sterling" but never "These cost five sterling". The abbreviations "ster." and "stg." are sometimes used. The term "British pound" is sometimes incorrectly used in less formal contexts, and it is not an official name of the currency.
The exchange rate of the pound sterling against the US Dollar is referred to as "cable" in the wholesale foreign exchange markets. The origins of this term are attributed to the fact that in the 1800s, the GBP/USD exchange rate was transmitted via transatlantic cable. Forex traders of GBP/USD are sometimes referred to as "cable dealers". GBP/USD is now the only currency pair with its own name in the foreign exchange markets, after IEP/USD, known as "wire" particularly in the forward FX markets, no longer exists after the Irish Pound was replaced by the euro in 1999.
There is apparent convergence of opinion and away from its association with Easterlings (Germanic traders) or other etymologies. Hence, the Oxford English Dictionary (and sources derived therefrom) state that the "most plausible" etymology is derivation from the Old English steorra for "star" with the added diminutive suffix "-ling", to mean "little star" and to refer to a silver penny of the English Normans. As another established source notes, the compound expression was then derived:
regarding the origin of the term "pound sterling", toward its derivation from the name of a small Norman silver coin,
silver coins known as "sterlings" were issued in the Saxon kingdoms, 240 of them being minted from a pound of silver... Hence, large payments came to be reckoned in "pounds of sterlings," a phrase later shortened...
— Encyclopædia Britannica, entry "pound sterling"
However, the perceived narrow window of the issuance of this coin, and the fact that coin designs changed frequently in the period in question, led Philip Grierson to reject this in favour of a more complex theory.
Another argument that the Hanseatic League was the origin for both the origin of its definition and manufacture, and in its name is that the German name for the Baltic is "Ost See", or "East Sea", and from this the Baltic merchants were called "Osterlings", or "Easterlings". In 1260, Henry III granted them a charter of protection and land for their Kontor, the Steelyard of London, which by the 1340s was also called "Easterlings Hall", or Esterlingeshalle. Because the League's money was not frequently debased like that of England, English traders stipulated to be paid in pounds of the "Easterlings", which was contracted to "'sterling".
For further discussion of the etymology of "sterling", see sterling silver.
The currency sign for the pound is £, which is usually written with a single cross-bar (as on sterling bank notes), though a version with a double cross-bar (₤) is also sometimes seen. This symbol derives from medieval Latin documents; the Roman words libra, solidus, and denarius (£sd) referred to pounds, shillings and pence in the British pre-decimal (duodecimal) currency system and the black-letter "L" was the abbreviation for libra, the basic Roman unit of weight.
The ISO 4217 currency code is GBP, formed from "GB", the ISO 3166-1 alpha-2 code for the United Kingdom, and the first letter of "pound". It does not stand for "Great Britain Pound" or "Great British Pound". Occasionally, the abbreviation "UKP" is used but this is non-standard because the ISO 3166 country code for the United Kingdom is GB (see Terminology of the British Isles). The Crown dependencies use their own (non-ISO) codes: GGP (Guernsey pound), JEP (Jersey pound) and IMP (Isle of Man pound). Stocks are often traded in pence, so traders may refer to pence sterling, GBX (sometimes GBp), when listing stock prices.
A common slang term for the pound sterling or pound is quid, which is singular and plural, except in the common phrase "Quids in!". The term may have come via Italian immigrants from "scudo", the name for a number of coins used in Italy until the 19th century; or from Latin 'quid' via the common phrase quid pro quo, literally, "what for what", or, figuratively, "An equal exchange or substitution".