At least in DC, they're distinct. The taxi service sends actual city-licensed taxis to pick you up, and the rate you pay is based on the meter (though you stil

At least in DC, they're distinct. The taxi service sends actual city-licensed taxis to pick you up, and the rate you pay is based on the meter (though you still pay for it via their app). UberX uses cars licensed as livery vehicles (like the black car service), and the rate is set per mile or minute or whatever by Uber, but they're mid-range cars like Priuses rather than towncars.