1. (尤指在著书或研究方面的)合作，协作
Collaboration is the act of working together to produce a piece of work, especially a book or some research.

2. 合作(或协作)的成果
A collaboration is a piece of work that has been produced as the result of people or groups working together.

3. 通敌;勾结敌人
Collaboration is the act of helping an enemy who is occupying your country during a war.

1. act of working jointly

e.g. they worked either in collaboration or independently

Synonym: coaction

2. act of cooperating traitorously with an enemy that is occupying your country

Synonym: collaborationismquislingism