Definition of "sinew"

[S]he loſt a noble and renowned brother, in his loue toward her, euer moſt kinde and naturall: with him the portion and ſinew of her fortune, her marriage dowry: with both, her combynate-husband, this well-ſeeming Angelo.

c. 1603–1604 (date written), William Shakespeare, “Measure for Measure”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act III, scene i], page 72, column 2

The Bodies of Men, Munition, and Mony may justly be called the ſinews of War, yet of them the two firſt are more neceſſary, for Men and Arms have means to find Mony and Meate: but Mony and Meate cannot ſo eaſily find Soldiers and ſwords.

1658, Walter Raleigh, “A Collection of Political Observations (Confirmed by Reason and Experience) Advertising Princes, Statesmen, and Private Persons how to Demean Themselves in All Fortunes and Events”, in The Cabinet-Council: Containing the Cheif[sic] Arts of Empire, and Mysteries of State; […], London: Published by John Milton; printed by Tho[mas] Newcomb for Tho[mas] Johnson […], page 101

Good company and good discourse are the very sinews of virtue.

1653, Iz[aak] Wa[lton], The Compleat Angler or The Contemplative Man’s Recreation. Being a Discourse of Fish and Fishing, […], London: […] T. Maxey for Rich[ard] Marriot, […]; reprinted as The Compleat Angler (Homo Ludens; 6), Nieuwkoop, South Holland, Netherlands: Miland Publishers, 1969,

And now to London with Triumphant march, / There to be crowned Englands Royall King: / From whence, ſhall Warwicke cut the Sea to France, / And aske the Ladie Bona for thy Queene: / So ſhalt thou ſinow both theſe Lands together, / And hauing France thy Friend, thou ſhalt not dread / The ſcattred Foe, that hopes to riſe againe: […]

c. 1591–1592 (date written), William Shakespeare, “The Third Part of Henry the Sixt, […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene vi], pages 157–158

[I]t were to be wiſhed that we tried the restrictive arts of government, and made law the protector, but not the tyrant of the people. […] [W]e ſhould then find that wretches, now ſtuck up for long tortures, left luxury ſhould feel a momentary pang, might, if properly treated, ſerve to ſinew the ſtate in times of danger; […]

1766, [Oliver Goldsmith], “The Same Subject Continued”, in The Vicar of Wakefield: […], volume II, Salisbury, Wiltshire: […] B. Collins, for F[rancis] Newbery, […]; reprinted London: Elliot Stock, 1885, page 123