Zodiac celestial coordinate system, or more specifically an ecliptic coordinate system, which takes the ecliptic as the origin of latitude and the Sun's position at vernal equinox as the origin of longitude. The English word ' derives from ', the Latinized form of the Ancient Greek "zōidiakòs kýklos" (), meaning "cycle or circle of little animals". "Zōidion" () is the diminutive of "zōion" (, "animal"). The name reflects the prominence of animals (and mythological hybrids) among the twelve signs. The zodiac was in use by the Roman era, based on concepts inherited by Hellenistic astronomy from Babylonian astronomy of the Chaldean
Stigma (letter) part of the minuscule writing style of Greek from the 9th and 10th centuries onwards. It is based on the lunate form (Ϲ) of the letter sigma. With many other ligatures, it was used to print Greek during the early-modern era. Between the 18th and 19th centuries, the use of ligatures in print gradually diminished. The στ ligature was among the last to go, around the middle of the 19th century. The name, "stigma" (), is originally a common Greek noun meaning "a mark, dot, puncture", or generally "a sign", from the verb ("(I) puncture"); the related but distinct word