noun
Refers to the start and finish of something as a pair. Often used in formal or written contexts.
物語の終始を簡単に説明してください。
Please briefly explain the beginning and end of the story.
noun, noun or participle which takes 'suru'
doing something from start to finish;
Used as a noun or with する to mean carrying out an action or maintaining a state from beginning to end without change.
彼は会議の間、終始笑顔だった。
He kept smiling throughout the meeting.
プロジェクトを終始リードした。
She led the project from start to finish.
adverb
from beginning to end; throughout; consistently
Adverbial use meaning 'all the way through' or 'the whole time'. Common in both speech and writing.
試合は終始激しい攻防が続いた。
The match was fiercely contested from beginning to end.
彼女は終始冷静だった。
She remained calm the whole time.