Merger
noun, verbal noun
Join and join with each other. This is a merger.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own. Just remember that 合 is read as ごう here. Who orchestrated this merger? Good ol' grandpa ごういち.
アメリカ合衆国は、私が生まれた年にテキサスを併合しました。
The United States of America annexed Texas the year I was born.