 The taxi expression is also being used in Hong Kong, New Zealand, and some other countries, but hasn't been used there as a general synonym for start fee.The origin is a taxi expression for the minimum charge for hiring a taxi, to which the rate per kilometre or mile and a rate per minute is usually then added up to a minimum taxicab road speed.When the passenger steps inside the taxicab, the flagfall condition is triggered and the taxicab driver can start the taximeter.