When you do page setup in Microsoft products you get to choose between Portrait or Landscape. Many other computer software programs have the same terms for how you want to print on a rectangular sheet of paper.
Abbott and Costello performed the classic "Who's on first?" baseball sketch in their 1945 film "The Naughty Nineties." Here is the video clip of that classic http://www.youtube.com/watch?v=sShMA85pv8M If you have never watched this skit I highly recommend it. Sometimes in my household we have these conversations. We come to things from different perspectives.
When talking to your photographer you could easily be having this same skit except it would be about photography instead of baseball.
This is a landscape photograph taken in Cades Cove, Tennessee.
This is a portrait photograph taken in a home.
Portrait and Landscape
In photography these terms refer to a style of photography. When you are taking portraits the person is the main emphasis over objects. Portrait photography can be of one person or a group.
Landscape photography is another style of photography. Landscape is about photographing nature vistas.
Neither of these terms portraits or landscape in photography are used to refer to orientation of the print.
While many cameras use the rectangular format there are many cameras that use the square format like the Polaroid camera and a Hasselblad.
Telling a photographer you need a portrait photograph when you are referring to the orientation of the print can get you into the Abbott and Costello sketch of "Who's on first."
Use the terms vertical and horizontal when referring to orientation of the final photograph.
When printing on a Mac the screen that will pop up will look like this where you are picking a graphic and not words to help you with the orientation. The one on the left is vertical and the one of the right is horizontal.
One of the places I worked in the past before the computer had really come to be so dominate would ask for vertical or horizontal photos. I would give her what she asked for and then she would be quite upset.
I would find her note and show her she did ask for what she got--her problem was she didn't no what vertical or horizontal really were. She had them confused so often she started to draw out the orientation.
When you talk with your photographer or when photographers talk with their clients be sure you are talking the same language.