A Turkish dolmus (DOHLmoosh) is a shared taxi or minibus running a predetermined route, with each passenger paying only a portion of the normal fare.
(Sometimes I spell it "dolmush" to remind you that the final 's' is an 'scedilla' in Turkish, equivalent to 'sh' in English.)
Dolmus means "filled:" the car or minibus waits at the beginning of its route until most or all of its seats are filled. Passengers can get out anywhere along the route, or ride to the end, for a single set fare that's the same for all passengers no matter what their destination.