Ictus \Ic"tus\, n. [L., fr. icere, ictum, to strike.]

1. (Pros.) The stress of voice laid upon accented syllable of a word. Cf. Arsis.

2. (Med.) A stroke or blow, as in a sunstroke, the sting of an insect, pulsation of an artery, etc.

Source: Webster's Revised Unabridged Dictionary (1913)