The word derives from the Old English scir, itself a derivative of the Proto-Germanic skizo (cf. Old High German scira), meaning care or official charge. In the UK, "shire" is the original term for what is usually known now as a county; the word county having been introduced at the Norman Conquest of England. The two are nearly synonymous. Although in modern British usage counties are referred to as "shires" mainly in poetic contexts, terms such as Shire Hall remain common. Shire also remains a common part of many county names.
In regions with so-called rhotic pronunciation such as Scotland, the word shire is pronounced //. In non-rhotic areas the final R is silent unless the next word begins in a vowel. When shire is a suffix as part of a placename in England, the vowel is unstressed and thus usually shortened and/or monophthongised: pronunciations include //, or sometimes //, with the pronunciation of the final R again depending on rhoticity. In many words, the vowel is normally reduced all the way to a single schwa, as in for instance Leicestershire // or Berkshire //. Outside England, and especially in Scotland and the US, it is more common for shire as part of a placename to be pronounced identically to the full word, as a result of spelling pronunciation.
The system was first used in Wessex from the beginning of Anglo-Saxon settlement, and spread to most of the rest of England in the tenth century, along with West Saxon political control. In Domesday (1086) the city of York was divided into shires. The first shires of Scotland were created in English-settled areas such as Lothian and the Borders, in the ninth century. King David I more consistently created shires and appointed sheriffs across lowland shores of Scotland.
The shire in early days was governed by an Ealdorman and in the later Anglo-Saxon period by royal official known as a "shire reeve" or sheriff. The shires were divided into hundreds or wapentakes, although other less common sub-divisions existed. An alternative name for a shire was a "sheriffdom" until sheriff court reforms separated the two concepts. The phrase "shire county" applies, unofficially, to non-metropolitan counties in England, specifically those that are not local Unitary authority areas. In Scotland the word "county" was not adopted for the shires. Although "county" appears in some texts, "shire" was the normal name until counties for statutory purposes were created in the nineteenth century.
"Shire" also refers, in a narrower sense, to ancient counties with names that ended in "shire". These counties are typically (though not always) named after their county town. The suffix -shire is attached to most of the names of English, Scottish and Welsh counties. It tends not to be found in the names of shires that were pre-existing divisions. Essex, Kent, and Sussex, for example, have never borne a -shire, as each represents a former Anglo-Saxon kingdom. Similarly Cornwall was a British kingdom before it became an English county. The term 'shire' is not used in the names of the six traditional counties of Northern Ireland.