Hospitalisation, Hospital Admission, Admission To A Hospital, Institutionalized
Noun and する verb
にゅういん
病じょうがあっ化し、入院する事になりました。
His condition deteriorated and they decided he's to be hospitalized.
入院中は、たいくつであくびが止まらなかったよ。
While I was hospitalized, I was so bored that I couldn't stop yawning.
今度、乳癌で入院することになったんです。
I'm going to be hospitalized due to breast cancer soon.
If you end up in a situation where you have to enter an institution it's called hospitalization. Hopefully you aren't there for very long.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.