A stand for many lights
In present-day English a candelabrum is an ornamental holder, usually with several arms, that carries more than one candle. It rests on a table, an altar, or the floor. Dictionaries still leave room for a slightly older, wider sense: a stand for lamps as well as candles. That wider sense is closer to the Latin object the word first named. A menorah is often described as a special case of the same furniture, but the English noun itself is general. It names the branched stand, not a particular rite.
Two routes from the same Latin noun
English did not inherit this spelling from Old English. Speakers already had candle, taken from Latin candela through the church, and they had a native compound candeltreow, literally candle-tree, for a stand that held lights. That older compound died out. What replaced it came in two waves from one Latin noun, candelabrum.
The first wave arrived in the late fourteenth century through Old French. Middle English wrote the French form as chaundelabre or chaundeler and still used it for a candlestick. That line of borrowing is the ancestor of chandelier. After long use as an ordinary word for a candle holder, English respelt the French descendant in the mid-eighteenth century and narrowed its job: a chandelier hangs from a ceiling. In the seventeenth century the French spelling had also named a military shelter, which is one reason the lighting sense needed a later, clearer form.
The second wave is the learned Latin shape still spelled candelabrum. It is a direct loan, not filtered through French sound change. Merriam-Webster dates the English noun to 1811; other dictionaries give a first-attestation window of 1805 to 1815. By that date Latin was the language of antiquaries, clergy, and people who collected bronze and silver plate. They reached back to the classical name for a standing light rather than stretching chandelier across every branched fixture. The two English words are doublets: the same Latin source, different paths, different furniture.
Candle plus a tool ending
Latin candelabrum comes apart cleanly. The first half is candela, a wax or tallow light, a torch, or a candle. That noun is built on the verb candere, to shine or to gleam white. Behind the verb sits a Proto-Indo-European root reconstructed as kand- or, in some accounts, (s)kend-, with the sense to shine. Related forms include Sanskrit cand-, to give light, and candra-, shining or the moon, and Welsh cann, white. Greek kandaros, coal, is sometimes placed in the same family, though that link is less secure. English candle, candid, candidate, candor, and incandescent all rest on the same Latin verb of brightness.
The second half is an instrumental suffix. Latin used -bulum for a thing you do something with. After stems that already contained an l, the suffix often appeared as -brum or -abrum. The extra a in candelabrum is analogical, copied from nouns built on verbs. So the whole formation is, in outline, the implement for a candle. Classical Latin treated it as a neuter noun of the second declension: singular candelabrum, plural candelabra. Older masculine variants candelaber and candelabrus are recorded, but the neuter form is the one English borrowed.
Roman writers applied the word to a simple candlestick, a branched stand, a hanging light, or a lampstand, sometimes of costly workmanship. A remark preserved from Varro explains the name in the most practical way: the object in which one fixes a candela is called a candelabrum. Candles were ordinary among Romans and Etruscans. Oil lamps did the same job in ancient Greece, which is one reason this Latin family of candle words has no native Greek twin of the same shape.
From one socket to many arms
Because Latin candelabrum could mean a single stick as well as a branched piece, English had to sort out a crowded set of names. Candlestick stayed for the simple shaft. Chandelier, after the eighteenth-century respelling, became the hanging cluster. Candelabrum, arriving as a Latinism in the early nineteenth century, settled on the standing branched holder. That standing-versus-hanging split is English housekeeping, not a rule Latin required.
The Latin plural came along for the ride and caused lasting number trouble. Candelabra is the classical plural, yet speakers often treat candelabra as a singular and then add an English -s. Candelabrums exists but is rare. Style guides that want the Latin pattern still prefer candelabrum in the singular and candelabra in the plural; everyday prose is messy in both directions. The mess is a sign that the loan never fully naturalized its grammar.
French candélabre, Italian candelabro, Spanish candelabro, German Kandelaber, and Russian kandelyabr show the same Latin noun traveling as a cultural object-name across Europe. They are cousins of the English learned form, not descendants of Old English candle-tree. The older native compound had already named the stand as a tree of candles. Latin named it as a tool. English kept the tool.
The suffix is the whole story
Once -brum is read as the thing for, candelabrum is no more mysterious than candlestick built in Latin instead of English. The shine-verb under candela also explains why a word for a metal stand shares a root with candid and incandescent: the candle was named for brightness before the stand was named for the candle. Keep the later English split with chandelier in mind, and the two doublets stop colliding. One hangs. The other stands. Both still point at the same Roman implement for a light.