Learner's definition of COLLABORATE
to work with another person or group in order to achieve or do something
— often + on or in
They collaborated on a book about dogs.
The pair collaborated with each other on the film.
Several doctors collaborated in the project.
— sometimes followed by to + verb
to give help to an enemy who has invaded your country during a war
The writers worked in collaboration to produce the book.
He worked in close collaboration with French scientists.
He was accused of collaboration with the enemy.