late 14c., treatise on astronomy by Claudius Ptolemy of Alexandria, extended in M.E. to other works on astrology or astronomy, from O.Fr. almageste,
from Arabic al majisti,
"the" + Gk. megiste
"the greatest (composition)," from fem. of megistos,
superl. of megas
"great" (see mickle
). Originally titled in Gk. Megale syntaxis tes astronomios
"Great Work on Astronomy;" Arab translators in their admiration altered this.