The Winter Solstice generally falls between the 20th and 23rd of December. It is the time of year when the sun is closest to the horizon, before it starts to climb higher again, and the days lengthen. In ancient times, when the light and heat of the sun were a key part of survival, this event was a cause of much celebration.
The Romans called it Dies Natalis Invicti Solis "the birthday of the Unconquered Sun." They marked the event with the festival Saturnalia; named after Saturn, the god of agriculture, which would most benefit from the return of longer days. It was a grand public holiday, marked by feasting and present-giving. Slaves ate and drank with their masters, and no war was declared or fought during this time.
Ancient Britons and Northern Europeans also celebrated the Winter Solstice with the festival of Yule. The Middle English term was Yole, which came from the Anglo-Saxons name, Geōl or Geōla. The Norse cognate was Jól, which survives in the Scandinavian Jul. One theory suggests that the Norse jōl became the Old French jolif "festive, merry, pretty," which has become joli / jolie in French, and jolly in English.
The sun, as such a life-sustaining element, has been a sacred symbol for millenia, and Yule is a time to celebrate the sun's re-birth and the lengthening day.
Helios, or Helius, was the Ancient Greek Titan god of the sun, and was sometime connected with the god Apollon (Apollo). From his name came Heliodorus "gift of Helios", Heliodora and Heliodoro. His Roman counterpart was Sol, the Latin word for "sun", which is now found in Spanish and Portuguese, the Italian word Sole, and Soleil in French.
Similar-sounding is the Norse word: Sól, from which the name Solveig "sun" + "strength" is said to be a derivative. Her international variations include Sølvi, Sylvi, Solvej, Solvig, Sylvei and Solva.
Many Nordic names contained the element sol. Solan, Solvar, Solbjørn "sun + bear", and Solmund "sun + protector" are masculine names. Sola, Soley, Sólbjørt "sun + shining", Solbjørg "sun + rescue, stronghold", Solbritt "Sol+Britta", Solfrid "sun + beloved, beautiful", Solgerd "sun + protection", Solhild "sun + battle", Solkatla "sun + helmet, cauldron" and Sóllilja "sun + lily" are feminine names.
[NB: It is worth noting that it is thought the original element in many of these names was "hall" and not "sun" although the sun meaning is used as a modern meaning and is certainly the origin of Soley and Sollilja]
In English, our word for sun comes from the Old English sunne. Sunngifu, or the Latinised Sunniva, was a Saxon name meaning "sun gift." Sunday and Sunshine are also occasionally used as first names.
The Welsh Haul "sun" is found in the names Heulfryn "sun + hill", and Heulwyn, Heulwen "sunshine", Grian is the Gaelic word for sun, and is thought to have once been an Irish sun goddess.
One of the key parts of ancient Yule was the burning of Yule logs. These had the practical function not only of keeping warm and bringing light to the dark winter months, but they were also thought to encourage the sun to rise again. They were believed to bring good luck into the home. British tradition had a large log chosen on Christmas Eve and dragged home in a procession. It was decorated with ribbons, blessed, and left to burn over the twelve days of Christmas. By the 18th century, the Yule log had become a Yule candle, lit in homes on Christmas Eve.
There are many names that reflect the idea of the fire of the Yule log, or the flame of the Yule candle.
The Gaelic Áed (modern Aodh) was one of the most popular names in early Ireland, borne by many kings and saints, which means "fire". Appropriately, it was the name of a Celtic god of the sun.
Its many derivatives include Áedán (Aodhan, Aidan, Aiden etc), Áedach (Aodhach), Áedhal (Aodhal), Áedgen (Aoidhghean), Áeducán (Aodhagán), Conláed (Conlao, Conleth) and Cináed (Cionaodh, Kenneth) for boys and Áednat (Aodhnait) and Áedammair (Aodhamair) for girls. There is also a possibility that the Irish name Fintan has the meaning "white fire".
The Greek goddess Hestia (Vesta in Latin) was goddess of the hearth, home, cooking and sacrificial flame. Her name literally meant "hearth". The god Hephaistos / Hephaestus (or Vulcan to the Romans) was the god of fire in connection with metalworking. Pyrros (Pyrrhos, Pyrrhus) is derived from the Greek πυρ (pyr) "fire" and was borne by several figures in Greek history and mythology.
Azar is the Persian word for "fire," and a feminine given name. Shula "flame" in Arabic is used for girls, as is, the related, Şule in Turkish. Fiammetta is an Italian name related to fiamma "flame" which has been in use since the Middle Ages and Nina means "fire" in Quechua and Aymara.
There is also the Latin Ignatius, which already existed in the name Egnatius, but whose spelling was altered in connection with the Latin ignis "fire" and Cole which was used as a medieval diminutive for Nicholas, but whose origins lie with the Old English col "coal."
Phoenix is the name of a mythical Greek bird who is consumed by fire, and, like the sun at the solstice, is reborn from the ashes. In connected terms, Anastastius, or the feminine Anastasia, is derived from the Greek word for "resurrection" which could be connected to the Winter Solstice.