What does gnomonical mean?
Gnomonical is a specialized adjective relating to a gnomon, the pointer whose shadow indicates time on a sundial. It is especially associated with gnomonical hours, the unequal units into which daylight was historically divided. Unlike modern clock hours, which have fixed lengths, gnomonical hours lengthened or shortened with the seasons according to the amount of daylight available. The word can also describe a gnomonic map projection, in which great circles on the globe appear as straight lines on the map. Its use is therefore concentrated in technical, historical, and scientific contexts rather than ordinary conversation. Although the shorter form gnomonic is more familiar, gnomonical remains a precise and useful term when discussing sundials, traditional time measurement, or the geometry of map projections.
adjectiveRelating to a gnomon, especially the shadow-casting indicator of a sundial. The term can also describe a map projection in which great circles appear as straight lines.
- Relating to a gnomon, especially the shadow-casting indicator of a sundial.
- Relating to a map projection in which great circles appear as straight lines.
"The gnomonical hours on the sundial varied with the seasons."
"The museum's display explains how gnomonical hours varied with the length of daylight."
"Using a gnomonical projection, the cartographer plotted great circles as straight lines."
A gnomonical hour was not a fixed 60 minutes: it stretched with summer daylight and shrank in winter.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of gnomonical
Gnomonical ultimately derives from the Greek gnōmōn, meaning an indicator or pointer and associated with knowing, through Latin gnomon and English gnomon. The English adjective was formed by adding the suffix -ical to gnomon. Related English words include gnomonic, gnome, and gnosis, all reflecting the same ancient Greek root associated with knowledge or knowing.
Related word forms
How gnomonical is actually used
This is a formal, specialized term used chiefly in discussions of sundials, historical timekeeping, and map projections. It is uncommon in everyday English.
Easily confused with gnomonical
A gnomon is the pointer or shadow-casting part of a sundial, whereas gnomonical is the adjective relating to a gnomon or to related concepts such as gnomonical hours.