Sorting, Organization, Adjustment
Noun and する verb
せいり
このアパートの住民の部屋はみんなきちんと整理されています。
This apartment's residents' rooms are all neatly arranged.
整理整とんすることは大切です。
Organizing well is important.
修学旅行で撮った写真を整理しました。
I organized the photos from my field trip.
When you arrange something according to reason, the result is an arrangement.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.