the union or combining of two or more things into one; merger, amalgamation, or joining together.
二社が合体して新しい会社を設立した。
Two companies merged to establish a new firm.
ロボットアニメでは複数の機体が合体して巨大ロボになる場面がよくある。
In robot anime, it's common for multiple units to combine into a giant robot.
異なるアイデアを合体させて新製品の企画書を作った。
I combined different ideas to create a proposal for a new product.
in biology, the conjugation or fusion of gametes or cells (i.e., two cells joining together).
藻類の一種では、二つの配偶子が合体して新しい個体を作る。
In a species of algae, two gametes fuse to form a new individual.
a euphemistic term for sexual intercourse; somewhat colloquial or childish, and not typically used in formal contexts.
その小説では『合体』という婉曲表現で男女の関係が描かれていた。
In that novel, the relationship between a man and a woman was described using the euphemism 'gattai' (union).