Welcome masa969! Here's a look at the terms used for seating sections from a theatrical site:
http://www.talkinbroadway.com/rialto/past/1999/8_5_99.html

Because auditorium and ticket terminology varies from one theatre to another, it is not surprising that many customers are confused when it comes to ordering tickets. How, then, should the various sections of a theatre be labeled? Some terms are preferred because they may sound more elegant than others: "terrace" instead of "first balcony," "family circle" instead of "second balcony." While the fancy labels may be desirable for some theatres, more accurate terms are probably a better choice in most cases. Almost any box office treasurer will attest that a surprising number of ticket buyers don't even understand the term "orchestra." Suffice it to say that theatregoing should be made as easy as possible. The following are the most commonly used seating terms:

Front Auditorium: Orchestra or Stalls (England)

Middle Auditorium: Mezzanine, Dress Circle, Front Balcony, First Balcony, Boxes, Side Terrace, Side Balcony, Loge, Parterre, Galleries (England), and First Tier

Rear Auditorium: Balcony, Rear Orchestra, Family Circle, Second Balcony, Rear Balcony, The Gods (England), Second Tier, and Second Terrace

In the US there's also a slang term for the furthest, and highest, seats in the back of the theatre or auditorium, notoriously the worst seats in the house: the nosebleeds.