Cooperation
Collaboration, Joint
noun, する verb, の adjective
People working together on the same thing is cooperation.
きょうどう
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.
トーフグと日清が、豆腐と河豚味のカップラーメンを、共同開発するらしいよ。
Apparently Tofugu and Nisshin are going to collaborate to make tofu and fugu flavored cup noodles.
トーフグは、北朝せんと共同して、金色の金正日人形を生さんしています。
Tofugu produces golden Kim Jong Il dolls in cooperation with a North Korean firm.
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.