Linnaeus named⁹ the genus Ceropegia in 1737 in his Genera plantarum. Linnaeus referred to the description and picture of a plant in the Horti Malabarici as the plant for which the genus was created. In 1753 he named this as Ceropegia candelabrum.
Above we have the iconotype of the Indian plant that Linnaeus named as Ceropegia candelabrum in 1753, as depicted¹³ in the Horti Malabarici of Henricum Rhede (or Reede) tot Drakestein published in 1689. The candelabrum bit gives it away when you see the way the flowers are arranged. Of course, some of you born after the invention of electric light may not have seen any candelabra or chandeliers.
There have been two possible explanations of the origin of the word Ceropegia. Linnaeus never explained it, as far as I know.
The earliest explanation I can find is from 1793. In the first volume¹² of Philipp Andreas Nemnich's Allgemeines Polyglotten-Lexicon der Naturgeschichte mit erklaerenden Anmerkungen (General Polyglot-Lexicon of Natural History with explanatory Remarks), he writes about Ceropegia:
Keropegion ist der griechische Name eines Leuchters für Wachslichter. Darnach führt diese Pflanzengattung den obigen Namen, weil der Bau ihrer Krone einige Aehnlichkeit mit dem Leuchter hat.
Keropegion is the Greek name for a chandelier/candlestick for wax candles. Hence this genus of plants bears the above name, because the structure of its crown is somewhat similar to a chandelier/candlestick.
The general name for Ceropegia in German was given as Der Leuchter, which means "chandelier" or "candlestick". In French le candelabre. In Dutch Kaarskroon, "candle-crown". In Danish lysestagen and Swedish ljusstaken, both meaning "candlestick".
In 1810, the fourth volume of the Encyclopædia Londinensis had the origin of Ceropegia as:
[κηροπηγɩον, Gr a candelabre, or lamp-stand.]
The only dictionary I could find that had the word keropegion is a Greek to Latin dictionary that is regarded as the most complete of all Ancient Greek dictionaries. The Thesauri linguæ Græcæ by Henrico Stephano (aka Henr. Stephanus, Henri Estienne or Henri Etienne) was first published in 1572. Dictionary entries for Ancient Greek words fill 3,165 pages in the first three volumes and further information on the Greek language fills 997 pages of the fourth volume.
The word keropegion is in the second¹⁴ of the four volumes. There are no examples given of its use in manuscripts. The Thesauri linguæ Græcæ would have been the standard work for those students who wanted to learn proper Ancient Greek from its publication in the 16th century on to the 19th century, well after the time of Linnaeus. Linnaeus certainly knew it and probably owned it. I emailed the Linnean Society of London to see if they had his copy. They kindly answered, noting that the Linnean collections they received had none of his reference works - "In fact the absence of general reference works from the collection is a curiosity: no dictionaries, thesauri, or word lists (except those contained in larger works, or written by Linnaeus himself)." They suggested that I email Uppsala University Library. A librarian there kindly replied today (19/7/2021). They have no Greek dictionaries of any kind in their collection of personal books owned by Linnaeus. However, they have had a copy of the Thesauri linguæ Græcæ in the University Library since before 1650. Linnaeus would have had access to that copy, as he became a student at Uppsala University in 1728.
The complete entry for the word is:
Κηροπήγɩον, ου, tὸ, Candelabrum, Vbi cerei depanguntur.
Keropegion, Candlestick, where candles are driven in.
Lewis & Short's Latin Dictionary has the Latin word candelabrum⁶ as meaning "a candlestick, a branched candlestick, a chandelier, candelabrum, or also lamp-stand, light-stand, sometimes of exquisite workmanship".
So, the first species named appears to be called "candlestick candelabrum" - Ceropegia candelabrum.