0 an organized event in which people swim a long distance in order to raise money for charity (= organizations that give money, food, or help free to those who are in need, or that provide money for causes such as medical research):
The competition pool hosts swimathons and galas throughout the year.
A swimathon organized by Darlington Rotary Club raised £6,500.
The swimathon aims to raise £2.5million for local charities.
By next Sunday I have to increase this distance by another 250m to reach 1000m for the swimathon we are doing.
