When arriving at the airport, your wife will need to locate her Terminal first, and then the gate; this is very important.
The terminals in some airports are connected – i.e., passengers can access any terminal (walk/train/shuttle) after they’ve been screened at any of the airport’s checkpoints.
Some airport terminals are completely disconnected; this means if you need to go to Terminal B to after you’ve gone through security in Terminal A you will need to go tough security again in Terminal B. This is important as it could have a significant effect on her timing. So it’s important to know the departure and layover airports (if any), as well as her Terminal information.
From a traveller’s point of view, I think you can make this distinction:
Terminals are the buildings which may have several gates. Gates are the exits from/entrances to the aircrafts.
E.g. for JFK list of all terminals: http://www.airport-jfk.com/terminals.php.
Say, here are the gates for terminal 4: http://www.jfkiat.com/maps/retail.pdf
Gates may have a direct entrance to the aircraft, or indirect (via e.g. a shuttle bus)
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