Cooperation
Collaboration, Joint
noun, verbal noun, の adjective
People working together on the same thing is cooperation.
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.
チームメイトとの共同作業は楽しいです。
Collaborative tasks with teammates are fun.
ここは学生が共同で使うコーワーキングスペースです。
This is a co-working space for students to share.
彼は共同の貯金をこっそり使い果たしてしまった。
He secretly used up our joint savings.