English LILAC is a common garden ornamental small tree, and a color name derived from its flower. Here's how LILAC's etymology is summarized in eight of today's English dictionaries. The last one above, Chambers, is incomplete but surely correct: Lilac is assuredly from Persian ''lilak'', a documented variant of the more standard ''nilak'' = "a little blue", "blueish", which is the Persian dimunitive of the Persian ''nil'' = blue or indigo. The thing that's highly questionable is the claimed Arabic (and Spanish) language on the path of descent. The first problem is that I can't find anybody citing an attestation of a ''līlak'' word at a sufficiently early date in Arabic. The second problem lies in the history of the introduction of the Lilac word into Europe. The early European meaning was for the small tree (or bush), and not the color; the color meaning was secondary and tied to the blueish flower on this particular tree. Here's a quote from the book "Lilacs: the genus Syringa", by John L. Fiala (year 2002) (viewable at books.google.com/books?id=rYatjOH-LbAC) In similar vein, here's from Wikipedia talking about the Common Lilac (''Syringa vulgaris''): In modern Turkish the word is spelled ''leylak'' and means Lilac tree and Lilac color. The venerable etymology dictionary by Walter Skeat (1888) (downloadable archive.org/details/etymologicaldict00skeauoft) derives the English from the Turkish, the spelling of which Skeat has as ''leilaq''. Skeat says the Turkish is from Persian, and he cites the 19th century Richardson's Persian-Arabic-English Dictionary (downloadable archive.org/details/dictionarypersia00johnuoft), wherein are the Persian words ''līlaj'' = ''līlang'' = indigo or blue; and ''nīlak'' = blueish. Richardson's contains no Arabic word along the lines of ''Lilac''. The closest to Lilac of any word in Arabic in Richardson's is "nīlaj" = indigo, and also Arabic ''nīlīy'', which is translated as "blue, [or] livid [color], [or] blackish" (and neither of those words are capable of generating ''lilak" in Arabic). Older English spellings for lilac included "laylock", "lilack" and "lilock". The English etymology dictionary by Ernest Weekly (1921) (downloadable archive.org/details/etymologicaldict00weekuoft/) states that Lilac's path of descent is "Old French (now only in plural ''lilas''), Spanish, Arabic ''lilak'', Persian ''lilak'',... [et cetera].... Earlier ''laylock'' is via Turkish ''leilaq''." There, Weekly's statement is that the deceased English wordform ''laylock'' came via one path while the surviving wordform ''lilac'' came via another path. That makes no sense of the evidence. There are no attestations of the Persian word meaning the bush: Only the color word was in Persian. The language that changed the primary meaning from the color to the bush must be on every path of descent. Which language was that? Arabic provides no hard info to answer that question because the word is not attested in Arabic either as a color or as a bush (except at a date too late). But since the bush generally couldn't flower in the climate of the Arabic speaking lands, it's highly unlikely that it was Arabic that changed the meaning to the bush. Spanish couldn't've borrowed an oral dialectical Arabic word for the Persian color word because the date, early 17th century, is way too late for Spanish borrowings from Arabic. Today's official dictionary of the Spanish language, the DRAE (online at buscon.rae.es/draeI/), says the Spanish is from French. It also says the French is from Arabic ("del fr. lilac, este del ár. līlak, este del persa lila[n]ǧ o lilang...."). The official dictionary of the French language says too that the French is not from Spanish (online at cnrtl.fr/definition/lilas). It says the first attestion in French is year 1605 spelled ''lilac'' and meaning the lilac bush. The color sense is not recorded in French until 1757 and was an extension of the botanical meaning. What was the origin of the 1605 French? The official dictionary of the French language often has detailed word etymologies, but in this case it has a terribly short answer with no supporting citations and no supporting facts: "Empr. à l'ar. līlāk" = "borrowed from Arabic līlāk". No explanation for how French was borrowing a word for an ornamental flower tree that does not flower in Arabic-speaking lands. A word with no attestations in Arabic writings! Question: What hard facts are today's dictionaries going on when they unanimously say the word is from Arabic (except for Chambers Dictionary which merely ducks the question)?