in prosody, 1570s (n.) "a foot of two syllables, the first short or unaccented, the second long or accented;" 1580s (adj.), "pertaining to or employing iambs," from Late Latin iambicus, from Greek iambikos, from iambos "metrical foot of one unaccented followed by one accented syllable; an iambic verse or poem," traditionally said to be from iaptein "to assail, attack" (in words), literally "to put forth, send forth" (in reference to missiles, etc.), but Beekes says "doubtless of Pre-Greek origin."
The meter of invective and lampoon in classical Greek since it was first used 7c. B.C.E. by Archilochus, whose tomb, Gaetulicus says, is haunted by wasps; iambics of various length formed the bulk of all English poetry before 20c. and a great deal since. The iambic of classical Greek and Latin poetry was quantitative.
in prosody, a foot of two syllables, the first short or unaccented, the second long or accented, 1842, from French iambe (16c.) or directly from Latin iambus "an iambic foot; an iambic poem," from Greek iambos "metrical foot of one unaccented followed by one accented syllable" (see iambic). Iambus itself was used in English in this sense from 1580s. In Greek, the measure was said to have been first used by satiric writers.
[The Iambus] is formed constantly by the proper accentuation of familiar, but dignified, conversational language, either in Greek or English : it is the dramatic metre in both, and in English, the Epic also. When the softened or passionate syllables of Italian replace the Latin resoluteness, it enters the measure of Dante, with a peculiar quietness and lightness of accent which distinguish it, there, wholly from the Greek and English Iambus. [Ruskin, "Elements of English Prosody, for use in St. George's Schools," 1880]
1540s, "having or displaying the qualities of a hero," shortened from heroical (early 15c., also heroycus) "noble, magnanimous," from Latin heroicus "of a hero, heroic, mythical," from Greek hērōikos "of or for a hero, pertaining to heroes," from hērōs (see hero (n.1)). In some modern uses, "having recourse to extreme measures." The Heroic Age, semi-mythical prehistoric period in Greece, ended with the return of the armies from the fall of Troy. Related: Heroically. Heroic verse (1610s), decasyllabic iambic, is from Italian.
Hymnal measure (a quatrain, usually iambic, alternately rhymed) is so called for being the preferred verse form for English hymns (such as "Amazing Grace"). It has been popular in English secular poetry as well, "though it almost always suggests the hymn, directly or ironically" [Miller Williams, "Patterns of Poetry," 1986].
mid-13c. "that which is given" (c. 1100 in surnames), from a Scandinavian source such as Old Norse gift, gipt "gift; good luck," from Proto-Germanic *geftiz (source also of Old Saxon gift, Old Frisian jefte, Middle Dutch ghifte "gift," German Mitgift "dowry"), from *geb- "to give," from PIE root *ghabh- "to give or receive." For German Gift, Dutch, Danish, Swedish gift "poison," see poison (n.).
Sense of "natural talent" (regarded as conferred) is from c. 1300, perhaps from earlier sense of "inspiration, power miraculously bestowed" (late 12c.), as in the Biblical gift of tongues. Old English cognate gift is recorded only in the sense "bride-price, marriage gift (by the groom), dowry" (hence gifta (pl.) "a marriage, nuptials"). The Old English noun for "a giving, gift" was giefu, which is related to the Old Norse word. Sense of "natural talent" is c. 1300, perhaps from earlier sense of "inspiration" (late 12c.). The proverbial gift horse was earlier given horse:
No man ought to looke a geuen hors in the mouth. [Heywood, 1546]
The modern form perhaps traces to Butler's "Hudibras" (1663), where the tight iambic tetrameter required a shorter phrase:
He ne'er consider'd it, as loth
To look a Gift-horse in the mouth.