guilder (n.)

c. 1300, "made of gold," from gold (n.) + -en (2); replacing Middle English gilden, from Old English gyldan. Gold is one of the few Modern English nouns that form adjectives meaning "made of ______" by adding -en (as in wooden, leaden, waxen, olden); those that survive often do so in specialized senses. Old English also had silfren "made of silver," stænen "made of stone," etc.

From late 14c. as "of the color of gold." Figurative sense of "excellent, precious, best, most valuable" is from late 14c.; that of "favorable, auspicious" is from c. 1600. Golden mean "avoidance of excess" translates Latin aurea mediocritas (Horace). Golden age "period of past perfection" is from 1550s, from a concept found in Greek and Latin writers; in sense of "old age" it is recorded from 1961. San Francisco Bay's entrance channel was called the Golden Gate by John C. Fremont (1866). The moralistic golden rule earlier was the golden law (1670s).

Whatsoever ye would that men should do to you, do ye even so to them [Matthew vii.12]

Do not do unto others as you would that they should do unto you. Their tastes may not be the same. [George Bernard Shaw, 1898]

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."