sinew definition
Use sinew in a sentence. LINK / CITE ADD TO WORD LIST. noun. The definition of a sinew is a tendon, the fibrous tissue that joins muscle and bones or any source of strength or power. An example of sinew is the Achilles tendon in the back of the ankle. (figuratively) Muscle; nerve; nervous energy; vigor; vigorous strength; muscular power. 2  A string or chord, as of a musical instrument. ( 3 figuratively) That which gives strength or in which strength consists; a supporting member or factor; mainstay; source of strength (often plural).