Noun, する verb, and の adjective
かいせい
四月から、JR山手線のダイヤが改正されます。
The schedule for the JR Yamanote Line will be revised in April.
インターネットの改正料金、もうチェックしましたか？
Have you checked the revised Internet rates?
市民団体は、公共の場でおならを禁止する法律の改正を求めた。
Citizen groups demanded a revision of the law banning farting in public.
Renew and make something correct. When you do this, you are doing a revision. Ah, much better now.
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.