Sinew

Noun

 * 1)  A tendon.
 * 2) Vigorous strength; muscular power.
 * 3)  Source of acquiring strength (often plural).

Derived terms

 * sinewy

Thesaurus
amperage, arm, armipotence, authority, backbone, beef, beefiness, bite, bitingness, black power, brawn, brawniness, brute force, charge, charisma, clout, cogence, cogency, compulsion, cuttingness, dint, drive, duress, effect, effectiveness, effectuality, elasticity, energy, flower power, force, force majeure, forcefulness, full blast, full force, guts, heftiness, huskiness, impressiveness, incisiveness, influence, involuntary muscle, ligament, main force, main strength, mana, might, might and main, mightiness, mordancy, moxie, muscle, muscle power, muscularity, musculature, nervosity, nervousness, physique, pillar, pizzazz, poignancy, poop, potence, potency, potentiality, power, power pack, power structure, power struggle, powerfulness, prepotency, productiveness, productivity, puissance, pull, punch, push, sinewiness, sinews, stamina, steam, strength, strong arm, strong language, superiority, superpower, tendon, thew, thewiness, thews, tone, trenchancy, validity, vehemence, vigor, vigorousness, vim, virility, virtue, virulence, vitality, voluntary muscle, wattage, weight