knell

Short definition from Wiktionary

Verb

1. 1
   To ring a bell slowly, especially for a funeral; to toll.
2. 2
   To signal or proclaim something (especially a death) by ringing a bell.
3. 3
   To summon by, or as if by, ringing a bell.

Noun

1. 1
   The sound of a bell knelling; a toll (particularly one signalling a death).
2. 2
   A sign of the end or demise of something or someone.

Proper noun

1. 1
   A surname.