ἰσοταχῶς
isotachōs

Greek adverb

Last edited: 2025-02-03
Primary meaning at constant speed
Literal translation at equal speed
Variants
ἰσοταχῶς isotachōs
Edited by

at constant speed adverb of movement

Ἐπιζητεῖται δὲ ἐν τούτοις, πῶς ἴσων ὄντων τῶν τεταρτημορίων τοῦ ζῳδιακοῦ κύκλου ὁ ἥλιος ἰσοταχῶς κινούμενος διὰ παντὸς ἐν ἀνίσοις χρόνοις διαπορεύεται τὰς ἴσας περιφερείας. Ὑποκείται γὰρ πρὸς ὅλην τὴν ἀστρολογίαν ἥλιόν τε καὶ σελήνην καὶ τοὺς εʹ πλανήτας ἰσοταχῶς καὶ ἐγκυκλίως καὶ ὑπεναντίως τῷ κόσμῳ κινεῖσθαι.

‘And it is a matter of question concerning these things: how - while the fourth parts of the zodiac are equal - does the sun, moving through each of them at constant speed, pass equal arcs in unequal times? For it is assumed regarding all of astronomy, that the sun and the moon and the 5 planets move at constant speed and in a circle and in a manner contrary to the cosmos.’

— Geminus 1.18-19

Genre: astronomy
Date: 1st century BCE

Geminus. 1975. Géminos, Introduction aux Phénomènes, ed. G. Aujac. Paris: Les Belles Lettres. 5


Cite this entry
APA (7th)
Peeters, T. (2025). ἰσοταχῶς (Lemma #1292). The ZODIAC Glossary: A Cross-Cultural Glossary of Ancient Astral Science. https://zodiacglossary.github.io/lemma/1292/

Chicago (Author-Date)
Peeters, T. (2025). ἰσοταχῶς (Lemma #1292). The ZODIAC Glossary: A Cross-Cultural Glossary of Ancient Astral Science. https://zodiacglossary.github.io/lemma/1292/

MLA (9th)
Peeters, T. (2025). ἰσοταχῶς (Lemma #1292). The ZODIAC Glossary: A Cross-Cultural Glossary of Ancient Astral Science. https://zodiacglossary.github.io/lemma/1292/

Harvard
Peeters, T. (2025) ἰσοταχῶς (Lemma #1292), The ZODIAC Glossary: A Cross-Cultural Glossary of Ancient Astral Science. Available at: https://zodiacglossary.github.io/lemma/1292/ (Accessed: February 2, 2026).

BibTeX
@misc{zodiac1292,
	note = {[Online; accessed 2026-02-02]},
	author = {Peeters, Thomas},
	year = {2025},
	title = {ἰσοταχῶς ({Lemma} #1292)},
	url = {https://zodiacglossary.github.io/lemma/1292/},
	howpublished = {https://zodiacglossary.github.io/lemma/1292/},
}