academy

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

• noun A school for special instruction.
• noun A secondary or college-preparatory school, especially a private one.
• noun The academic community; academe.
• noun Higher education in general. Used with the.
• noun A society of scholars, scientists, or artists.
• noun Plato's school for advanced education and the first institutional school of philosophy.
• noun Platonism.
• noun The disciples of Plato.

from The Century Dictionary.

• noun [capitalized] Originally, a public pleasure-ground of Athens, consecrated to Athene and other deities, containing a grove and gymnasium, where Plato and his followers held their philosophical conferences; hence, Plato and his followers collectively; the members of the school of Plato.
• noun A superior school or institution of learning.
• noun An association of adepts for the promotion of literature, science, or art, established sometimes by government, and sometimes by the voluntary union of private individuals.

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

• noun A garden or grove near Athens (so named from the hero Academus), where Plato and his followers held their philosophical conferences; hence, the school of philosophy of which Plato was head.
• noun An institution for the study of higher learning; a college or a university. Popularly, a school, or seminary of learning, holding a rank between a college and a common school.
• noun A place of training; a school.
• noun A society of learned men united for the advancement of the arts and sciences, and literature, or some particular art or science
• noun A school or place of training in which some special art is taught
• noun (Paint.) a drawing usually half life-size, in crayon or pencil, after a nude model.

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

• noun with the Academia.
• noun A body of established opinion in a particular field, regarded as authoritative.

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

• noun a secondary school (usually private)
• noun a learned establishment for the advancement of knowledge
• noun a school for special training
• noun an institution for the advancement of art or science or literature