n. & v.
n. 1 the sound of a bell, esp. when rung solemnly for a death or funeral. 2 an announcement, event, etc., regarded as a solemn warning of disaster.
v. 1 intr. a (of a bell) ring solemnly, esp. for a death or funeral. b make a doleful or ominous sound. 2 tr. proclaim by or as by a knell (knelled the death of all their hopes). ring the knell of announce or herald the end of.
[ OE cnyll, cnyllan: perh. infl. by bell ]