The Kharulian word for “letter” (of the alphabet) is únus [ˈu.nus], a word that owes its existence to a bizarre morphological coincidence.
The Kharulians first learned to write from the Muipidans, who used a logographic script. The Old Muipidan word for a logographic character was xuhnuse, and its definite form was xuhnusephado, adding -pha to indicate the noun class for flat things and -do, the definite article. As usual, the Kharulians borrowed the definite form and treated it as an accusative, producing the Old Kharulian nominative hunuzépat.
By Classical Kharulian, this had become unzhípat, and was often applied to the script as a whole, not just single characters. And that’s when Kharulian scribes noticed the resemblance to words for languages (e.g. Iskulyípat “the Kharulian language”), made with the suffix -pat (related to fat “speech”). In fact, unzhípat looks very much like it’s the genitive plural of a noun únus (compare ánas “mist”, enzhi “of mists”) plus the suffix -pat. So Kharulian scribes started using únus as the word for “letter”, reanalyzing unzhípat as “speech of the letters”.