'One' is pronounced with a /w/ found nowhere else in English — a quirk from western Middle English dialects.
The lowest cardinal number; a single unit or entity; the first positive integer.
From Old English 'ān,' meaning 'one, single, sole,' from Proto-Germanic *ainaz, from the PIE root *oi-no- meaning 'one, unique.' The same root produced Latin 'ūnus,' which gave rise to French 'un,' Spanish 'uno,' and English borrowings like 'unite,' 'universe,' and 'unique.' The modern pronunciation /wʌn/ with an initial /w/ developed in western dialects of Middle English and became standard by the 17th century, though the spelling preserved the older vowel. Key roots