Origin of the alloy metal
Although the origin of the word “sterling” is controversial, there is general agreement that the sterling alloy originated in continental Europe, and was being used for commerce as early as the 12th century in the area that is now northern Germany.
Origin of the word “sterling”, used to refer to the silver alloy
The word “sterling”, used in reference to the 925 grade of silver, emerged in England by the 13th century. The terms “sterling” and “pound sterling” acquired their meaning in more than a century, and from convergent sources. There are three possible origins for the word “sterling”. Two originate from 12th and 13th century coinage, and one is generally discounted. The word could have derived from the Old English word “stiere”, meaning “strong, firm, immovable”.
Starling theory, discounted
Although marks of birds have been used in some coins of Edward the Confessor, sterling is not likely to have been derived from starling, as the word for starling at the time was spelled stær.
Mint mark theory
The 1955 edition of the Oxford English Dictionary states that the early Middle English name sterling was presumably descriptive of small stars that were visible on early Norman pennies. (Old English: steorling.)