Wikipedia
Avsey is a Russian male first name. There are several theories as to its origins. According to one, it is simply a colloquial variant of the name Yevsey. Another possibility is that "Avsey", as well as Asey and Osey , are colloquial variants of the name Absey , alternatively spelled Apsey , which until the end of the 19th century was included into the official Synodal Menologium. Finally, it is possible that "Avsey" derives from the Old East Slavic word "авсень"/"овсень" (avsen/ovsen), meaning New Year's Eve, which in ancient times corresponded to the first day of spring.
The diminutive of "Avsey" is Avseyka .
The patronymics derived from "Avsey" are "" (Avseyevich; masculine) and its colloquial form "" (Avseich), and "" (Avseyevna; feminine). The patronymics derived from "Absey" are "" (Abseyevich; masculine) and "" (Abseyevna; feminine).