noun, adverb
next year; the following year
Used to refer to the year after the current or a specified year. Often appears in narrative or formal contexts.
あくる年、彼は海外に留学した。
The following year, he studied abroad.
あくる年の春、新しい学校が開校し
In the spring of the next year, a new school opened.
来年 is the standard word for 'next year' in everyday conversation. あくる年 is more literary and often used in storytelling or formal writing.
From 明くる (next, following) + 年 (year). 明くる is an attributive form of the classical verb 明く (to dawn, to begin), now used as a fixed modifier.