noun, verbal noun
If you enter a group, it's called enrollment or enlistment. You're joining the group.
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.
The application for the enrollment was printed in small type.
You won't gain anything out of joining that religious organization.
The Tofugu baseball team will hold tryouts at the Tofugu office on Friday, October 23rd.