1A highly productive prefix attached to Sino-Japanese (kanji) compounds to mean 'new' or 'newly-' — 新製品 ('new product'), 新型 ('new model'), 新人 ('newcomer'), 新入生 ('new student'), 新発見 ('new discovery'), 新発売 ('newly on sale'), 新婚 ('newlywed'), 新作 ('new work/release'), 新刊 ('newly published book'). Pervasive across news, ads, and corporate writing in modern Japanese. Read as しん (shin). Native-reading equivalents — にい〜 (新妻 'newlywed wife') and あら〜 (新手 'fresh hand') — live under a separate dictionary entry.
新製品の発売日が来週に決まった。
The release date for the new product has been set for next week.
うちの部署にも新入社員が3人入った。
Three new hires joined our department too.
新型のスマートフォンに買い替えた。
I bought the latest model of smartphone.
好きな作家の新作が来月発売される。
A new release from my favourite author comes out next month.
新幹線で東京から大阪まで2時間半かかる。
It takes two and a half hours from Tokyo to Osaka on the Shinkansen.
2Used as a noun meaning 'newness' or 'novelty' — a somewhat formal, written-register usage. Found in essays, criticism, and discussions of art (新を求める 'to seek novelty', 古きを捨て新を取る 'discard the old and take the new'). In everyday speech, 新しさ or 新鮮さ would be more natural.
芸術家は常に新を求め続けるものだ。
An artist is the kind of person who is always seeking novelty.
古典の様式に新を加え、独自の作風を築いた。
He added something new to the classical style and established a distinctive aesthetic of his own.
3An abbreviation for 新暦, the Gregorian calendar. Japan switched from the lunisolar 旧暦 ('old calendar') to the Gregorian 新暦 in Meiji 5 (1872), so in historical sources or notes about traditional events you'll sometimes see 新 written beside a date to contrast with 旧 — e.g., 新7月15日 means 'July 15 by the new calendar'. Rare in standalone everyday use; appears mainly in calendar/history/traditional-events contexts.
旧暦の七夕は新で言うと8月になることが多い。
Tanabata by the old calendar usually falls in August by the new (Gregorian) calendar.
4The Xin dynasty (Hsin) of China — a short-lived dynasty (9–23 CE) founded by Wang Mang, who had usurped the Western Han throne as a former imperial in-law. It collapsed with Wang Mang's death, after which the Eastern Han was established. Encountered almost only in Chinese / East Asian historical contexts; treated as a history-vocabulary term.
王莽が建てた新は、わずか15年で滅びた。
The Xin dynasty founded by Wang Mang lasted a mere fifteen years before collapsing.