I. ˈsin-(ˌ)yü also ˈsi-(ˌ)nü noun
Etymology: Middle English sinewe, from Old English seono; akin to Old High German senawa sinew, Sanskrit syati he binds
Date: before 12th century
1. : tendon ; especially : one dressed for use as a cord or thread
2. obsolete : nerve
3.
a. : solid resilient strength : power
astonishing intellectual sinew and clarity — Reynolds Price
b. : the chief supporting force : mainstay — usually used in plural
providing the sinew s of better living — Sam Pollock
II. transitive verb
Date: circa 1614
: to strengthen as if with sinews