from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A comprehensive treatise on astronomy, geography, and mathematics compiled by Ptolemy about A.D. 150.
- n. Any of several medieval treatises concerned with astronomy or alchemy.
from the GNU version of the Collaborative International Dictionary of English
- n. The celebrated work of Ptolemy of Alexandria, which contains nearly all that is known of the astronomical observations and theories of the ancients. The name was extended to other similar works.
from The Century Dictionary and Cyclopedia
- n. The greatest work on astronomy before Copernicus, written in the second century a. d. by the Alexandrian astronomer Ptolemy.
Middle English almageste, from Old French, from Arabic al-majisti : al-, the + Greek megistē (suntaxis), greatest (composition), feminine of megistos, greatest, superlative of megas, great.(American Heritage® Dictionary of the English Language, Fourth Edition)