Terms used

Connecting Flights
Flights with intermediate stops and change of aircraft and possibly airline.
Example 1: Taking a flight from Johannesburg to Munich via Dubai. The first leg is from Johannesburg to Dubai Airport on EK764 (Emirates). Disembark the plane in Dubai. Once inside the terminal building, go through security and wait for the boarding gate to open for your next flight. No need to collect luggage. Board flight EK049 (Emirates)  to Munich.
Example 2: Taking a flight from Frankfurt to Cape Town via Johannesburg on Multiple Airlines. The first leg is from Frankfurt to Johannesburg on LH572 (Lufthansa). Disembark the plane in Johannesburg. Once inside the terminal building, go through passport control, and collect your luggage  Check in for your flight and wait for the gate to open. Board code share flight  LH347/SA327 (South African Airways)  to Cape Town


Direct Flights
Flight between two designated airports without change in Aircraft or Flight numbers, but may include a stop over. 
Example: Taking a flight from Dubai to Malta via Larnaca. The plane will land in Larnaca and there might be passengers leaving/boarding the plane.  If your final destination is Malta, you stay on board the aircraft until it arrives in Malta.
You only disembark the plane at your final destination

Disembark (to get off) the plane
Disembarking the aircraft can be done in two ways
- Via aircraft bridge: You will go from the plane directly into the terminal building
- via mobile staircase: You will climb down stairs and be transported to the terminal building via a bus service. At smaller airports you can sometimes walk from the plane to the terminal building. Watch a Video of Mobile stairs being attached to an aircraft after landing.

Non-stop Flights
A non-stop flight is made in a single leg and without intermediate stops between the departure and destination airport.
Example: Taking a flight from Frankfurt to Atlanta. The plane will fly directly from Frankfurt to Atlanta without making any stop overs.

Passport Control
The area inside the airport where passports are checked and stamped by Immigration control.
Your passport gets stamped when you leave or enter a country.
When you are a foreigner, you need to adhere to immigration control rules, and have the relevant visa to enter the country.

Transit
Passengers who stay at the airport for a short period, with the intention of proceeding to their final destination

Seat pitch
This is an indication of legroom, referring to the space between a point on one seat and the same point of the seat in front of it. It is affected by the thickness of the seat back.