green-colored stuff in plants, 1819, from French chlorophyle (1818), coined by French chemists Pierre-Joseph Pelletier (1788-1842) and Joseph Bienaimé Caventou (1795-1877) from chloro-, from Latinized form of Greek khlōros "pale green, greenish-yellow" (from PIE root *ghel- (2) "to shine," with derivatives denoting "green" and "yellow") + phyllon "a leaf" (from suffixed form of PIE root *bhel- (3) "to thrive, bloom").
Proto-Indo-European root meaning "to shine;" it forms words for "gold" (the "bright" metal), words denoting colors, especially "yellow" and "green," also "bile, gall," for its color, and a large group of Germanic gl- words having to do with shining and glittering and, perhaps, sliding. Buck says the interchange of words for yellow and green is "perhaps because they were applied to vegetation like grass, cereals, etc., which changed from green to yellow."
It forms all or part of: arsenic; Chloe; chloral; chloride; chlorinate; chlorine; chloro-; chloroform; chlorophyll; chloroplast; cholecyst; choler; cholera; choleric; cholesterol; cholinergic; Cloris; gall (n.1) "bile, liver secretion;" gild; glad; glance; glare; glass; glaze; glazier; gleam; glee; glib; glide; glimmer; glimpse; glint; glissade; glisten; glister; glitch; glitter; glitzy; gloaming; gloat; gloss (n.1) "glistening smoothness, luster;" glow; glower; gold; guilder; jaundice; melancholic; melancholy; yellow; zloty.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit harih "yellow, tawny yellow," hiranyam "gold;" Avestan zari "yellow;" Old Persian daraniya-, Avestan zaranya- "gold;" Greek khlōros "greenish-yellow color," kholos "bile, gall, wrath;" Latin helvus "yellowish, bay," Gallo-Latin gilvus "light bay;" Lithuanian geltonas "yellow;" Old Church Slavonic zlutu, Polish żółty, Russian zeltyj "yellow;" Latin galbus "greenish-yellow," fellis "bile, gall;" Lithuanian žalias "green," želvas "greenish," tulžis "bile;" Old Church Slavonic zelenu, Polish zielony, Russian zelenyj "green;" Old Irish glass, Welsh and Breton glas "green," also "gray, blue;" Old English galla "gall, bile," geolu, geolwe, German gelb, Old Norse gulr "yellow;" Old Church Slavonic zlato, Russian zoloto, Old English gold, Gothic gulþ "gold;" Old English glæs "glass; a glass vessel."
by 1895, loan-translation of German Photosynthese, from photo- "light" (see photo-) + synthese "synthesis" (see synthesis). Related: Photosynthetic. Another early word for it was photosyntax.
[T]he body of the work has been rendered into English with fidelity, the only change of moment being the substitution of the word "photosynthesis" for that of "assimilation." This change follows from a suggestion by Dr. Barnes, made a year ago before the American Association at Madison, who clearly pointed out the need of a distinctive term for the synthetical process in plants, brought about by protoplasm in the presence of chlorophyll and light. He proposed the word "photosyntax," which met with favor. In the discussion Professor MacMillan suggested the word "photosynthesis," as etymologically more satisfactory and accurate, a claim which Dr. Barnes showed could not be maintained. The suggestion of Dr. Barnes not only received tacit acceptance by the botanists of the association, but was practically approved by the Madison Congress in the course of a discussion upon this point. [The Botanical Gazette, vol. xix, 1894]
