Real Dictionary

contribute
verb: If something contributes to an event or situation, it is one of the causes of it.
verb: If you contribute to something, you say or do things to help to make it successful.
verb: To contribute money or resources to something means to give money or resources to help pay for something or to help achieve a particular purpose.

contribute in American English
to give or provide jointly with others; give to a common fund
intransitive verb: to give (money, food, etc.) to a common supply, fund, etc
transitive verb: to give (money, time, knowledge, assistance, etc.) to a common supply, fund, etc., as for charitable purposes

contribute in British English
to give (support, money, etc) for a common purpose or fund