godan verb (-ru), intransitive verb
Intransitive: something becomes compressed, shrinks, or shortens in physical size, length, or volume. Often used for materials, text, or time.
この布は洗うと約まる。
This cloth shrinks when washed.
説明が長すぎた
The explanation was too long, so it was shortened to just the main points.
godan verb (-ru), intransitive verb
become simpler; be summarized; become brief
Intransitive: something abstract (a story, explanation, procedure) becomes condensed, simplified, or summarized. Often implies a reduction to essentials.
複雑な手続きが約まって、申請が楽になった。
The complicated procedure was simplified, making the application easier.
彼の長い話が結局一言に約まった。
His long story was eventually summarized in a single word.