lyceum

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A hall in which public lectures, concerts, and similar programs are presented.
• noun An organization sponsoring public programs and entertainment.
• noun A lycée.

from The Century Dictionary.

• noun [capitalized] An ancient public gymnasium with covered walks outside of Athens, near the river Ilissus, where Aristotle taught philosophy; hence, the Peripatetic school of philosophy. See Aristotelian.
• noun A school for higher education preparatory to a university course. Compare college, 2 .
• noun A house or an apartment appropriated to instruction by lectures or disquisitions.
• noun An association for literary improvement.

from the GNU version of the Collaborative International Dictionary of English.

• noun A place of exercise with covered walks, in the suburbs of Athens, where Aristotle taught philosophy.
• noun A house or apartment appropriated to instruction by lectures or disquisitions.
• noun A higher school, in Europe, which prepares youths for the university.
• noun An association for debate and literary improvement.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A public hall designed for lectures or concerts.
• noun US A school at a stage between elementary school and college.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a public hall for lectures and concerts
• noun a school for students intermediate between elementary school and college; usually grades 9 to 12