>usu. elevated above the orchestra level

In the UK this level is called the orchestra stalls but is generally known as the stalls. In the USA I noticed that this is usually called the orchestra.

In the UK the seating names do vary but in a traditional theatre, if there are several levels, they are commonly called:
Stalls (lowest level), Circle, Dress Circle or Royal Circle (1st level looking down), Upper Circle or Grand Circle (2nd level looking down) and Balcony (right at the top), although there are exceptions.

There are sometimes boxes at the back of the stalls, at the side and further forward than the dress circle, similarly with the grand circle.

The site for London's Globe Theatre has some interesting theatre history. The construction of the the theatre, with space for the groundlings, was quite different to modern theatre. http://www.rdg.ac.uk/globe/