sinews
also ˈsi-(ˌ)nü
Noun
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 sinews of better living—Sam Pollock
Source