Etymology From Middle English quiver, from Anglo-Norman quivre, from Old Dutch cocare (source of Dutch koker, and cognate to Old English cocer (“quiver, case”)), from Proto-West Germanic *kokar (“container”), said to be from Hunnic, possibly from Proto-Mongolic *kökexür (“leather vessel for liquids”); see there for more. Replaced early modern cocker, the inherited reflex of that West Germanic word. The mathematical sense originated as German Köcher in a 1972 paper by Pierre Gabriel; it was likely chosen because a quiver contains arrows, while a digraph contains directed edges (also called "arrows").
Don Pedro: Nay, if Cupid have not spent all his quiver in Venice, thou wilt quake for this shortly.1598–1599 (first performance), William Shakespeare, “Much Adoe about Nothing”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act I, scene i], line 271:
Arrows were carried in quiver, called also an arrow case, which served for the magazine, arrows for immediate use were worn in the girdle.1786, Francis Grose, A Treatise on Ancient Armour and Weapons, page 39:
2
Figuratively A ready storage location for figurative tools or weapons.
[...] there was a little quiver fellow, and 'a would manage you his piece thus; and 'a would about and about, and come you in and come you in.c. 1596–1599 (date written), William Shakespeare, “The Second Part of Henry the Fourth, […]. Epilogue.”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act III, scene ii], line 281:
Etymology From Middle English quiveren, probably from the adjective.
1
To shake or move with slight and tremulous motion.
The birds chaunt melodie on euerie buſh, The ſnakes^([sic – meaning ſnake]) lies rolled in the chearefull ſunne, The greene leaues quiuer with the cooling winde, And make a checkerd ſhadow on the ground: [...]c. 1588–1593 (date written), William Shakespeare, “The Lamentable Tragedy of Titus Andronicus”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act II, scene iii], line 12:
And left the limbs still quivering on the ground.1712 (date written), [Joseph] Addison, Cato, a Tragedy. […], London: […] J[acob] Tonson, […], published 1713, →OCLC, Act IV, scene i, page 47:
2 more examples
Next moment with a rapid, nameless impulse, in a superb lofty arch the bright steel spans the foaming distance, and quivers in the life spot of the whale.1851 November 14, Herman Melville, chapter 84, in Moby-Dick; or, The Whale, 1st American edition, New York, N.Y.: Harper & Brothers; London: Richard Bentley, →OCLC, page 410:
And the moonlight on the Church seemed to shift and quiver—some pigeons perhaps had been disturbed up there.1919 October, John Galsworthy, chapter VIII, in Saint’s Progress, London: William Heinemann, published December 1919, →OCLC, part III, page 300: