common name of a type of small wildflower with a yellow bloom, 1777, perhaps (OED) a merger of two older names, gold-cups and butterflower. See butter (n.) + cup (n.).

also pay dirt, "profit, success," 1873, from pay (n.) + dirt (n.); a word from mining, where it was used by 1856 in a literal sense of "gravel or sand containing a sufficient amount of gold to be profitably worked."

1590s, "let out, cause to flow out; draw off (liquid)," by or as by a sluice, from sluice (n.). In gold-mining, "to scour or cleanse by a sluice," by 1859. Related: Sluiced; sluicing.

mid-15c., donour, "one who gives or bestows, one who makes a grant," from Anglo-French donour, Old French doneur (Modern French donneur), from Latin donatorem (nominative donator) "giver, donor," agent noun from past participle stem of donare "give as a gift," from donum "gift" (from PIE root *do- "to give").

As "person from whom blood is removed for transfusion," by 1875; in reference to those living or dead from whom organs or tissues are removed for transplantation, by 1918 (originally of guinea pigs).

1852, "lump of gold," probably from southwestern England dialectal nug "lump," a word of unknown origin [OED]. Another theory is that it is from a misdivision of an ingot. Transferred sense (of truth, etc.) is from 1859.

1721, official stamp of purity in gold and silver articles, from Goldsmiths' Hall in London, site of the assay office; see hall + mark (n.1). General sense of "mark of quality" first recorded 1864. As a verb from 1773.

1570s, "dye obtained from lac;" 1670s as "gold-colored solution of shellac," from obsolete French lacre, name for a kind of sealing wax, from Portuguese lacre, unexplained variant of lacca "resinous substance," from Arabic lakk, from Persian lak (see lac).

c. 1300, "adorn with (gold) wire," from wire (n.). From 1859 as "communicate by means of a telegraphic wire;" 1891 as "furnish with electrical wires and connections." Related: Wired; wiring.

also bi-metallic, "composed of two metals," 1864; see bi- "two" + metallic. In economics, "pertaining to the use of both silver and gold as standards in currency," 1876, from French bimétalique (Cornuschi).

"watercourse, dry stream bed," 1845, a California word, from American Spanish, in Spanish, "rivulet, small stream," perhaps from Latin arrugia "shaft or pit in a gold mine," which is apparently a compound of ad "to" (see ad-) + ruga "a wrinkle" (see rugae).