Sinew/ˈsɪnjuː/ Definition 1 of 2Pro Tip 1/3Physical Anatomy Sinew mainly refers to parts inside the body, so it's used in medical or biological contexts. The surgeon repaired the torn sinew with precision. Pro Tip 2/3Metaphor for Strength Used metaphorically, 'sinew' can describe anything that gives support like a tendon does. The sinews of the bridge were its massive steel cables. Pro Tip 3/3Physical Resilience In descriptions, 'sinew' conveys toughness and the ability to endure strain. The old oak tree's sinewy roots withstood the storm.