Several parts combine into one character.

Phonetic-semantic compound: 糸 (silk thread) + 冬 (winter — providing both phonetic value and semantic suggestion). The original oracle bone form showed a piece of thread with knots tied at both ends — the literal "end of a thread". Adding 冬 reinforced the meaning: winter is the ending season. So 終 covers thread-end, season-end, and any "ending" by extension. Three forms: 繁體 終 / 新字体 終 / 简体 终. Pairs with 始 (start, previous entry) — 始終 (shǐzhōng / shijū / 시종) is the classical CJK term for "from start to finish".

Mandarin: zhōng, level 1st tone (simplified 终). 终 in modern Chinese — note the spoken Mandarin verb for "to end" is more often 结束 (jiéshù) than 终, but compounds: 终点 (zhōngdiǎn, terminus / endpoint), 终于 (zhōngyú, finally / at last — extremely high frequency), 最终 (zuìzhōng, ultimately), 始终 (shǐzhōng, throughout / always), 终生 (zhōngshēng, lifelong). 终于 is one of the most useful intermediate-level Mandarin adverbs.

Japanese: on-reading シュウ (shū) for compounds — 終了 (shūryō, conclusion / end), 最終 (saishū, final / last), 終電 (shūden, last train of the day — the inverse of 始発), 終点 (shūten, terminal station), 終日 (shūjitsu, all day long). Kun-reading お.わる (o.waru, to end — intransitive) and お.える (o.eru, to finish — transitive) form another foundational intransitive/transitive pair. 終わる pairs with 始まる exactly.

The pair 始発 (first train) and 終電 (last train) define the daily commute window of every Japanese city dweller — the bookends of the train day.

Memory aid: thread (糸) + winter (冬) — the end of the thread, the end of the year, all endings.