hairspringEnglishOxford New American Dictionaryhairspring /ˈherˌspriNG, ˈhɛrˌsprɪŋ / ▸ noun a slender flat coiled spring regulating the movement of the balance wheel in a watch.
EnglishOxford New American DictionaryEnglishOxford New American Dictionary
EnglishOxford New American Dictionary