Why is a rat called “korost”? - briefly
The name comes from an Old Slavic root *kor‑ meaning “to gnaw” or “to bite,” which early speakers applied to the common rodent.
Why is a rat called “korost”? - in detail
The word “korost” designates a rat in several East‑Slavic dialects. It derives from the Proto‑Slavic root *kor‑, meaning “to gnash, to gnaw”. Adding the suffix ‑ost, which forms nouns denoting a characteristic or entity, yields a term that can be rendered as “the gnawer”.
Historical records show the form in 19th‑century folk collections and regional dictionaries, where it appears alongside standard Russian “крыса”. Literary examples occur in works by authors documenting rural speech, confirming its use in everyday language of peasants.
Morphologically, the suffix ‑ost parallels forms such as “жадность” (greed) from “жадный” (greedy). Consequently, “korost” emphasizes the animal’s habitual gnawing behavior rather than any taxonomic distinction.
Geographically, the term is attested in Ukrainian, Belarusian, and in Russian dialects of the north‑west and southern regions. In Ukrainian it appears as “корость”, preserving the same meaning. The Belarusian variant “корост” is listed in the national lexicon as a colloquial name for a rat.
Contemporary Russian reserves the word for dialectal or folkloric contexts; standard language prefers “крыса”. Researchers of Slavic linguistics cite “korost” when illustrating lexical diversity in animal nomenclature.
Key points
- Originates from Proto‑Slavic *kor‑ “to gnaw”.
- Suffix ‑ost creates a noun meaning “the gnawer”.
- Documented in 19th‑century folk literature and regional dictionaries.
- Used in Ukrainian, Belarusian, and specific Russian dialects.
- Modern usage limited to dialectal, folkloric, or linguistic study contexts.