/boʊθ/
[adjective] Used to talk about two people or things together, meaning the one as well as the other. For example, if both options are good, it means neither one is bad.
The word 'both' was imported from Viking invaders, quietly replacing the Old English word that had the same job for centuries.
The story of 'both' is really a story about invasion, language contact, and the slow replacement of one word by another. The word comes from Old Norse 'báðir', which meant 'both' in exactly the same way it does today. Old Norse was the language spoken by the Vikings who settled in large parts of northern and eastern England from the 8th century onwards. Over time, Old Norse báðir → Middle English 'bothe' → Modern English 'both', with the word arriving in written English records around the 12th century.
Before the Vikings brought their version of this word, Old English already had its own equivalent: 'bēgen' (masculine), 'bā' (feminine and neuter). These forms were in daily use among Anglo-Saxon speakers for centuries. But as Norse settlers and English speakers lived side by side — trading, marrying, and sharing communities — the simpler and more consistent Norse form gradually won out. 'Bēgen' and 'bā' faded away, leaving 'both' as the sole survivor.
Looking further back, both the Old Norse and Old English words share a common ancestor in Proto-Germanic '*bai-', which itself traces back to the Proto-Indo-European root '*bʰo-', meaning 'both' or 'two together'. This ancient root spread widely across the Indo-European language family. Latin had 'ambo' for 'both', Greek had 'amphō', and Sanskrit had 'ubhā' — all cousins of the English word 'both', each carrying the same ancient idea of pairing two things as a single unit.
What makes 'both' particularly interesting is how it survived without much change in meaning across thousands of years. While many words shift dramatically in meaning over centuries, 'both' has always done exactly the same job: it pulls two separate things together and treats them as one complete pair. Linguists call this kind of durable, simple word a 'function word' — it serves grammar rather than describing the world, which may explain why its meaning has remained so stable.
The word also sits at the centre of a fascinating grammatical question that trips up even careful writers: 'both of them are' versus 'both of them is'. Because 'both' always refers to two things treated together, it takes a plural verb in English — a rule that has been consistent since the Middle Ages. Interestingly, related words in other Germanic languages behave similarly. German 'beide' and Dutch 'beide', which share the same Proto-Germanic root, also require plural agreement, showing that this grammatical habit is very old indeed.