What does almagest mean?
The almagest is a comprehensive astronomical treatise that sets out mathematical models of celestial motion together with tables and rules for calculating the positions of the Sun, Moon, planets, and stars. The best-known almagest was compiled by the Greco-Roman mathematician Ptolemy in the second century CE. It became one of the most authoritative works of ancient astronomy and was later translated, revised, and expanded by scholars in the Islamic world before being transmitted back to medieval Europe. The word is usually reserved for historical scientific literature rather than modern astronomy textbooks, but it remains common in scholarship on the history of astronomy and mathematics. The Almagest is especially memorable because its geocentric model shaped European and Islamic astronomical thought for well over a thousand years, even though later observations eventually demonstrated that a heliocentric system better described the movements of the planets.
nounAn ancient or medieval astronomical treatise containing mathematical theories, observations, and tables for calculating the positions of celestial bodies. The term most often refers specifically to the influential second-century work compiled by Ptolemy.
- An ancient or medieval astronomical treatise, especially Ptolemy's influential second-century work on mathematical astronomy.
"Medieval scholars translated and annotated the Almagest, which remained an important astronomical authority for centuries."
"The translator's commentary clarified several difficult passages in the Almagest."
"Astronomers in the Islamic world produced revised versions of the Almagest and improved its tables."
The plural is used for multiple astronomical treatises of this kind; Ptolemy's work itself is normally referred to in the singular.
"Comparisons between the Almagest and later Arabic astronomical works reveal substantial changes in observational methods."
The Almagest passed from Greek astronomy into the Islamic world and then back into medieval Europe, shaping scientific thought for more than a thousand years.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of almagest
Almagest comes through Medieval Latin from Arabic al-majīstī, usually encountered in the fuller Arabic title al-Kitāb al-Majīstī, “the Book of the Greatest.” The Arabic name ultimately reflects Ptolemy's Greek designation of the work as the greatest treatise, based on the Greek words megistē, “greatest,” and megistos, “greatest” or “very great.”
How almagest is actually used
The word is specialized and usually appears in historical, mathematical, or astronomical contexts. It is normally capitalized when referring to Ptolemy's work; the lowercase form is more generally used for comparable astronomical compilations.
Easily confused with almagest
An almanac is an annual calendar often containing astronomical information, whereas the almagest is primarily an astronomical treatise and its theoretical models and tables.