1. a sinew, tendon; in plural, the tendons of the feet , (Iliad by Homer)

2. metaphorically in plural, τὰ νεῦρα τῆς τραγῳδίας, of lyric odes, their sinews, vigour , (Aristophanes Comicus); τὰ νεῦρα τῶν πραγμάτων (Aeschines Orator)

3. gut, cord made of sinew , for fastening the head of the arrow to the shaft, (Iliad by Homer): the cord of a sling , (Xenophon Historicus) (ML)