noun, adverb
after the end; after completion
Used as a noun or adverb to indicate the time after something has finished. Common in announcements, schedules, and formal writing.
終了後、会場の片付けをお願いします。
After the event ends, please help clean up the venue.
試験終了後に解答が配布
The answers were distributed after the exam finished.
後 (ご) is a suffix meaning 'after', but 終了後 is a fixed compound with a more specific temporal meaning.
Compound of 終了 (shūryō, 'end, completion') + 後 (go, 'after'). The reading ご for 後 is the standard on'yomi used in temporal compounds.