ictus

In medicine terms the difference between convulsion and ictus

is that convulsion is an intense, paroxysmal, involuntary muscular contraction while ictus is a sudden attack, blow, stroke, or seizure, as in a sunstroke, the sting of an insect, pulsation of an artery, etc.

As nouns the difference between rictus and ictus

is that rictus is a bird's gaping mouth while ictus is the pulse.

As nouns the difference between actus and ictus

is that actus is an ancient roman unit of length, approximately 355 metres while ictus is the pulse.