Alliance
noun, verbal noun, の adjective
We are of the same alliance. We are in an alliance.
どうめい
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
ああ、そういうことか。トーフグは一番のライバル会社と同盟を組んだんだよ。
Oh, now I see what happened. Tofugu formed an alliance with its closest competitor.