(sound/strike/toll) the death knell for/of something• The death knell for a revised Thanksgiving came when retailers began admitting their revenues had not improved after all.• Croson to be the death knell forminoritycontracting laws, many bigcityofficialsrefused to give up.• Nor is Mr Gore's loss going to be the death knell for the environment that Preston claims.• Was it the death knell of the nuclear industry or merely curfew time?• This would, in effect, finally sound the death knell for the Convention.• Energyanalyst Walt Patterson believes this would sound the death knell forresearch.