One’s business is picking up or dropping off? (4)
I believe the answer is:
taxi
'one's' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for taxi that I've seen before include "Prepare to fly" , "Public service vehicle" , "type of vehicle" , "move on ground before take-off" , "Minicab" .)