ictus

noun pl. -·tuses or -·tus

1. rhythmic or metrical stress, or accent
2. Med. a convulsion, stroke, or sudden attack

Etymology: L, a blow, stroke, metrical stress < pp. of icere, to strike, hit, beat < IE base *aik-, *ik-, spear, to strike with a sharp weapon > Gr aichmē, a spear