A congress is a formal meeting of representatives from different countries (or by extension constituent states), or independent organisations (such as different trade unions).
The term Congress was chosen for the US Congress to emphasise the status of each state represented there as a self-governing unit. Subsequently to the use of congress by the US legislature, the term has been adopted by many states within unions, and by unitary countries in the Americas, to refer to their legislature, although this usage does not correspond to the proper meaning of the word.
The term Congress is often identified with the presidential system of government.
Other countries with Congresses:
It has been used for meetings of independence-minded nationalists or revolutionaries:
(Note, the political parties mentioned above also began as groups of this type).
Congress is also part of the name of certain international bodies, such as
A Chess congress is a chess tournament, in one city, where a large number of contestants gather to play competitive chess over a limited period of time; typically one day to one week.