A narrative digression or self-contained story inserted into a larger work or conversation. Often used in literary or formal contexts.
This novel contains several episodes depicting the protagonist's past.
An interesting anecdote was told in the middle of his speech.
He inserted a short episode into the novel.
The teacher told an interesting anecdote between lessons.
There's an anecdote about how he struggled when he was young.
総和 (そうわ) is a homophone meaning 'sum total,' completely unrelated to 挿話, which means an inserted episode or anecdote.
episodic
Compound of 挿 (insert) and 話 (story), literally 'inserted story'. The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning.