When booking a flight, the terms "Direct" and "Non-Stop" are often used interchangeably, but they mean very different things.
Non-Stop Flight
This is what most travelers want. A plane that takes off at A and lands at B with no stops in between.
Direct Flight
Surprisingly, a "Direct" flight can stop for refueling or to pick up passengers, as long as the flight number does not change. You might even have to stay on the plane during the stop.
Always check the flight details carefully!