Webster's Revised Unabridged Dictionary · 1913

Lysis

Lysis (lī"sis) , noun

[New Latin, from Greek ly`sis.]

(Medicine) The resolution or favorable termination of a disease, coming on gradually and not marked by abrupt change.

It is usually contrasted with crisis, in which the improvement is sudden and marked; as, pneumonia ends by crisis, typhoid fever by lysis.