Real Dictionary

knell in American English
the sound of a bell, esp. of a bell rung slowly, as at a funeral
to call or announce by or as by a knell
to ring in a slow, solemn way; toll
intransitive verb: to sound, as a bell, esp. a funeral bell
noun: the sound made by a bell rung slowly, esp. for a death or a funeral
transitive verb: to proclaim or summon by, or as if by, a bell

knell in British English
noun: the sound of a bell rung to announce a death or a funeral
verb: to ring a knell