other

The word 'other' is one of the most fundamental terms in the English language, serving as both adjective and pronoun to mark difference, distinction, and the existence of alternatives.‌​‌​‍​‌​‍​‌​‍​‍​‍​‌​‍​‍​‍​‍​‍​‌​‍​‍​‍​‌​‌​‍​‌​‌​‌​‍​‌​‌​‌​‍​‌​‍ It appears in the earliest Old English manuscripts and has cognates in every Germanic language, yet its deeper history connects it to one of the most productive roots in Indo-European.

Old English 'ōþer' meant primarily 'second' — the second of two — and only secondarily 'different, not the same.' This sense of 'second' persists in archaic phrases like 'every other day' (every second day). The Old English form descends from Proto-Germanic *anþeraz, which can be analyzed as *an- (one) plus the comparative suffix *-þeraz, yielding a literal meaning of 'the more-one' or 'the one beyond.' This is precisely parallel to the PIE reconstruction *h₂énteros, built from *h₂ent- (front, forehead, face) plus the contrastive suffix *-teros, which was used specifically for distinguishing between two options — not three or more.

The PIE suffix *-teros is the same element that appears in Latin 'alter' (the other of two), Greek 'héteros' (other, different), and Sanskrit 'ántara' (other, interior). Latin 'alter' became enormously productive in English through borrowing: 'alternate,' 'alternative,' 'alteration,' 'altruism' (coined in French from Italian 'altrui,' from Latin 'alter'), and 'alter ego' all descend from it. This means that English possesses two reflexes of the same PIE word — the native 'other' and the borrowed 'alter' — each carrying different registers and connotations.

The Proto-Germanic form *anþeraz shows the characteristic Germanic dental fricative (the 'th' sound) that corresponds to Latin 't' by Grimm's Law. Compare English 'other' with Latin 'alter,' English 'three' with Latin 'tres,' English 'thou' with Latin 'tu' — the same systematic sound shift that separates Germanic from the rest of Indo-European.

In the Germanic languages, the cognates are immediately recognizable: German 'ander' (other), Dutch 'ander,' Swedish 'annan,' Danish 'anden,' Icelandic 'annar.' All preserve the core meaning of 'second, other.' Gothic 'anþar' shows the oldest attested Germanic form, with the dental fricative still spelled explicitly.

The semantic history of 'other' in English reveals a gradual broadening. In Old English, 'ōþer' primarily meant 'second' and was the standard ordinal numeral — Old English had no separate word for 'second' (the modern word 'second' was borrowed from French in the 13th century). Once 'second' arrived and took over the ordinal function, 'other' was free to specialize in the meaning 'different, additional, remaining.' This is a textbook case of how borrowing reshapes native vocabulary: a French loanword did not replace 'other' but rather allowed it to narrow and sharpen its meaning.

The compound 'another' (from 'an other,' literally 'one other') appeared in Middle English and gradually fused into a single word. 'Otherwise' dates to Old English 'on ōþre wīsan' (in another way). 'Either' and 'neither' also contain the PIE *-teros comparative element, though by a different route.

'Other' remains one of the 100 most common words in English and is used in virtually every register, from nursery speech ('the other one') to philosophy ('the Other' as a concept in phenomenology and ethics). Its frequency and its deep Indo-European ancestry make it one of the oldest continuously spoken words in the language.