col·lab·o·rate 
/kəˈlæbəˌreɪt/ verb
col·lab·o·rates; col·lab·o·rat·ed; col·lab·o·rat·ing /kəˈlæbəˌreɪt/ verb [no obj] 1 : to work with another person or group in order to achieve or do something
▪ The two companies agreed to collaborate. — 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 ▪ They collaborated to write a book. 2 disapproving : to give help to an enemy who has invaded your country during a war
▪ He was suspected of collaborating with the occupying army.
▪ The two companies agreed to collaborate. — 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 ▪ They collaborated to write a book.
▪ He was suspected of collaborating with the occupying army.
— col·lab·o·ra·tion /kəˌlæbəˈreɪʃən/ noun, plural col·lab·o·ra·tions
[count] ▪ The book is the product of a collaboration between two writers. = The book is a collaboration between two writers. ▪ an artistic collaboration [noncount] ▪ 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.
/kəˌlæbəˈreɪʃən/ noun, plural col·lab·o·ra·tions [count] ▪ The book is the product of a collaboration between two writers. = The book is a collaboration between two writers. ▪ an artistic collaboration [noncount] ▪ 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.
