/ɒv/, /əv/
[preposition] A word used to show belonging, connection, or relationship between things, or to describe what something is made from or about. For example, it tells us who owns something, what a group includes, or what a thing contains.
'Of' and 'off' were once the same word — only centuries of heavy use split them into two.
Few words in the English language carry as much quiet power as 'of'. It appears so constantly — threading through sentences, linking nouns, anchoring meaning — that we rarely stop to wonder where it came from. Yet this humble two-letter word has one of the oldest and most continuous histories in the language, stretching back beyond the earliest written records of English into the deep roots of the Germanic world.
The word descends directly from Old English 'of', which carried a surprisingly broad range of meanings: away, away from, from, out of, and off. It was used in both space and time — you could travel 'of' a place, or something could happen 'of' a certain hour. This Old English 'of' derived from Proto-Germanic *'aba', meaning 'away from' or 'off', which itself traces back to the Proto-Indo-European root *'apo-', meaning 'away' or 'off'. That ancient root is shared across an extraordinary number of languages: it gave Greek 'apo' (as in 'apostle', from Greek 'apostolos' meaning 'one sent away'), and Latin 'ab' or 'abs' (meaning 'from', seen in English words like 'absent' and 'absolve', which entered English via Old French).
In Old English, 'of' and 'off' were actually the same word. The distinction between them developed gradually during the Middle English period (roughly 1100–1500 CE), as the language simplified and speakers began to feel the need to separate the stressed form — used for physical separation, as in 'get off the horse' — from the unstressed form, which had evolved to signal relationship or belonging. By the time of Chaucer in the 14th century, 'of' was already doing much of the connective grammatical work it does today, appearing in phrases like 'the king of England' or 'a cup of wine'.
What is remarkable about 'of' is how dramatically its meaning narrowed and then specialised. In its Proto-Germanic and early Old English life, it was fundamentally about movement and separation — about things moving away from other things. Over the medieval period, this directional sense faded almost entirely from common use (surviving only in fossilised phrases like 'north of the river'), and 'of' became instead a word of connection, possession, and description. The journey from 'away from' to 'belonging to' is one of the great quiet reversals in English semantic history.
Today, 'of' is one of the most frequently used words in English — consistently ranking in the top five words by raw count in almost any large corpus of text. It does an enormous amount of grammatical labour: indicating possession ('the roof of the house'), describing material ('a bridge of stone'), expressing quantity ('a crowd of people'), and connecting abstract ideas ('a sense of wonder'). It is the connective tissue of the English noun phrase, so deeply embedded that removing it would cause the language to collapse in on itself. For such a small word, its story is anything but small.