yellowcake (n.)

Middle English yelwe, from Old English geolu, geolwe, "yellow," from Proto-Germanic *gelwaz (source also of Old Saxon, Old High German gelo, Middle Dutch ghele, Dutch geel, Middle High German gel, German gelb, Old Norse gulr, Swedish gul "yellow"), from PIE root *ghel- (2) "to shine," with derivatives denoting "green" and "yellow" (such as Greek khlōros "greenish-yellow," Latin helvus "yellowish, bay").

In Middle English it also was used of a color closer to blue-gray or gray, of frogs or hazel eyes, and as a translation of Latin caeruleus or glauco. The meaning "light-skinned" (in reference to black persons) is recorded by 1808. It was applied to Asiatics by 1787, though that first reference is to Turkish words for inhabitants of India.

Yellow peril translates German die gelbe gefahr. The sense of "cowardly" is by 1856, of unknown origin; the color was traditionally associated rather with jealousy and envy (17c.). Yellow-bellied "cowardly" is from 1924, probably a semi-rhyming reduplication of yellow; earlier yellow-belly was a sailor's name for a half-caste (1867) and a Texas term for Mexican soldiers (1842, based on the color of their uniforms). Yellow dog "mongrel" is attested from c. 1770; the slang sense of "contemptible person" is recorded by 1881. Yellow fever is attested from 1748, American English (jaundice is a symptom).

early 13c., "flat or comparatively thin mass of baked dough," from Old Norse kaka "cake," from West Germanic *kokon- (source also of Middle Dutch koke, Dutch koek "a cake, gingerbread, dumpling," Old High German kuohho, German Kuchen "a cake, a tart"). Not believed to be related to Latin coquere "to cook," as formerly supposed. Replaced its Old English cognate, coecel.

What man, I trow ye raue, Wolde ye bothe eate your cake and haue your cake? ["The Proverbs & Epigrams of John Heywood," 1562]

Extended mid-15c. to any flat, rounded mass. Extended from early 15c. to "a light composition of flour, sugar, butter and other ingredients baked in any form." To take the cake "win all, rank first" (often ironic) is from 1847, American English; piece of cake "something easy" is from 1936.

The let them eat cake story is found in Rousseau's "Confessions," in reference to an incident c. 1740, long before Marie Antoinette, though it has been associated with her since c. 1870; it apparently was a chestnut in the French royal family that had been told of other princesses and queens before her.