/ðæn/
[conjunction/adverb] A word used to compare two things, showing that one is different from or greater than the other. For example, you use it to say that something is bigger, better, or more important in relation to something else.
'Than' and 'then' were the same word in Old English — speakers only gradually split them apart over centuries.
The word 'than' reaches back to Old English, where it appeared as 'þonne' or 'þanne' — words that carried two meanings at once: comparison and time. A speaker of Old English might use the same word to say 'she is taller than her brother' and 'we arrived, and then we rested.' These two ideas — measuring one thing against another, and placing events in sequence — were, for centuries, carried by a single, flexible word. The separation of 'than' and 'then' into two distinct words happened slowly and unevenly across the Middle English period, roughly between the 11th and 15th centuries, as writers and speakers began to feel the need for greater precision.
The Old English 'þonne' itself descended from the Proto-Germanic root *þan-, a demonstrative particle that pointed outward — at a thing, a moment, or a contrast. This root is closely related to similar words in other Germanic languages: Old High German 'danne' (meaning 'then' or 'than'), Old Saxon 'than,' and Old Frisian 'thenne.' All of these cousins performed the same double duty, blending comparison with time in a way that modern English speakers would find confusing. The Germanic branch as a whole inherited this particle from Proto-Indo-European, where demonstrative roots beginning with *to- or *th- were used to point and distinguish.
What is remarkable is how long the ambiguity lasted. Even into the 14th and 15th centuries, Middle English manuscripts frequently used 'than' and 'then' interchangeably, with no consistent spelling or meaning to separate them. Chaucer, writing in the late 1300s, sometimes used forms that could be read either way. It was not until the Early Modern English period — the 15th to 17th centuries — that printers and grammarians began to enforce a cleaner distinction, gradually reserving 'then' for time and 'than' for comparison. Shakespeare's era was still not fully settled on this, and you can find both spellings doing both jobs in texts from the 1500s.
One of the most enduring grammatical debates attached to 'than' is whether it should be treated as a conjunction or a preposition — and this matters more than it might seem. If 'than' is a conjunction, you say 'she is taller than he is,' following it with a subject. If it is a preposition, you say 'she is taller than him,' following it with an object. Both usages have existed in English for centuries, and both appear in the works of respected writers. The preposition use — 'than me,' 'than him' — is natural in everyday speech, while formal writing often prefers the conjunction form. This small word has generated a surprisingly large amount of grammatical argument.
Despite its modest appearance, 'than' is one of the most frequently used words in the English language, sitting comfortably in the top hundred or so words by frequency. It is a function word — a word that does grammatical work rather than carrying heavy meaning on its own — and yet without it, expressing comparison becomes awkward and clumsy. Its journey from a broad, time-and-contrast particle in Proto-Germanic, through the fluid ambiguity of Old and Middle English, to its settled modern role as the word of comparison, is a quiet but telling example of how languages sharpen their tools over time, finding precision where there was once productive vagueness.