gramercy interj.

late 14c., grant "large, big" (early 12c. in surnames), from Anglo-French graunt and directly from Old French grant, grand (10c., Modern French grand) "large, tall; grown-up; great, powerful, important; strict, severe; extensive; numerous," from Latin grandis "big, great; full, abundant," also "full-grown;" figuratively "strong, powerful, weighty, severe," of unknown origin.

In Vulgar Latin it supplanted magnus and continued in the Romanic languages. The connotations of "noble, sublime, lofty, dignified," etc., were in Latin. In English it developed a special sense of "imposing." Meaning "principal, chief, most important" (especially in titles) is from 1560s; that of "of very high or noble quality" is from 1712. As a general term of admiration, "magnificent, splendid," from 1816. Related: Grander; grandest.

Grand jury is late 15c. Grand piano from 1797. The grand tour of the principal sites of continental Europe, as part of a gentleman's education, is attested by that name from 1660s. The Grand Canyon of the Colorado River in western U.S. was so called by 1869, popularized by Maj. John Wesley Powell, scientific adventurer, who explored it; earlier it had been known as Big Canyon. For grand slam see slam (n.2).

late 12c., "God's forgiveness of his creatures' offenses," from Old French mercit, merci (9c.) "reward, gift; kindness, grace, pity," from Latin mercedem (nominative merces) "reward, wages, pay, hire" (in Vulgar Latin "favor, pity;" in Medieval Latin "thanks; grace"), from merx (genitive mercis) "wares, merchandise" (see market (n.)). In Church Latin (6c.) it was given a specific application to the heavenly reward earned by those who show kindness to the helpless and those from whom no requital can be expected.

Meaning "disposition to forgive or show compassion" is attested from early 13c. Sense of "an act or exercise of forbearance or good will" is from c. 1300. As an interjection, attested from mid-13c. (short for may God have mercy, have mercy on me, etc.).  Many of the English senses are found earlier in French, but in French the word largely has been superseded by miséricorde except as a word of thanks. Sense of "discretionary action" (as in at (one's) mercy) is from mid-14c. Seat of mercy "golden covering of the Ark of the Covenant" (1530), hence "the throne of God," is Tyndale's loan-translation of Luther's gnadenstuhl, an inexact translation of Latin propitiatorium, ultimately a rendering of Hebrew kapporeth, literally "propitiatory."