"gad about, spend time in frivolous pleasure-seeking, especially with the opposite sex," 1809, of uncertain origin, perhaps a playful elaboration of gallant in an obsolete verbal sense of "play the gallant, flirt, gad about." Related: Gallivanted; gallivanting.
Young Lobski said to his ugly wife,
"I'm off till to-morrow to fish, my life;"
Says Mrs. Lobski, "I'm sure you a'nt",
But you brute you are going to gallivant."
What Mrs. Lobski said was right,
Gay Mr. Lobski was out all night.
He ne'er went to fish, 'tis known very well
But where he went I shall not tell.
["Songs from the Exile," in "Literary Panorama," London, 1809]
"to prance about in a self-satisfied manner," 1871, coined by Lewis Carroll in "Jabberwocky," apparently by blending gallop and triumph. "The sense in current use may vary according to different notions of what the sound expresses" [OED]. Related: Galumphing.
kind of large ship, 1520s, from French galion "armed ship of burden," and directly from Spanish galeón "galleon, armed merchant ship," augmentative of galea, from Byzantine Greek galea "galley" (see galley) + augmentative suffix -on. Developed 15c.-16c., it was shorter, broader, and with a higher stern superstructure than the galley. In English use, especially of Spanish royal treasure-ships or the government warships that escorted private merchant ships in the South American trade.
GALLEON. The accepted term for the type of ship which the Spaniards used in 1588; that is, an armed merchantman of exceptional quality, combining the strength of the mediaeval trader with some of the finer lines and fighting features of the GALLEY. [Sir Geoffrey Callender, "Sea Passages," 1943]
Italian agumented form of galea, galeaza, led to a different 16c. ship-name in English, galliass (1540s).
c. 1300, plural of Middle English galwe "gallows" (mid-13c.), from Old Norse galgi "gallows," or from Old English galga (Mercian), gealga (West Saxon) "gallows;" all from Proto-Germanic *galgon "pole" (source also of Old Frisian galga, Old Saxon galgo, Middle High German galge "gallows, cross," German Galgen "gallows," Gothic galga "cross"), from PIE *ghalgh- "branch, rod" (source also of Lithuanian žalga "pole, perch," Armenian dzalk "pole").
In Old English, also used of the cross of the crucifixion. Plural because made of two poles. Gallows-tree is Old English galg-treow. Gallows humor (1876) translates German Galgenhumor.