knell

Concise Oxford English Dictionary © 2008 Oxford University Press:
knell /nɛl/ literary

▶noun the sound of a bell, especially when rung solemnly for a death or funeral.

■ something regarded as a warning of disaster.

▶verb (of a bell) ring solemnly.

■ proclaim by or as if by a knell.

– origin OE cnyll (n.), cnyllan (v.), of W. Gmc origin; the spelling is perh. influenced by bell1.