A deathbed is the bed a person dies in. On his deathbed, a deathbed confession, a deathbed conversion.
It appears almost only in fixed phrases about last moments: a deathbed confession, a deathbed promise, a deathbed conversion. In law a statement made when somebody knows they are dying is admissible in some cases where hearsay otherwise would not be.
1noundeathbedThe bed a person dies in.
“On his deathbed, the old man asked his sons to forgive each other.”
deathbed is a bed.
Old English deathbedd, death plus bed. It once meant a grave as well as a bed.
Old English
dēaþbedd — deathbed; grave
Middle English
dethbed
English, today
deathbed
From Middle English dethbed, from Old English dēaþbedd (“deathbed; grave”), equivalent to death + bed. Cognate with Swedish dödsbädd (“deathbed”). Compare also Dutch sterfbed (“deathbed”), German Sterbebett and Totenbett (both “deathbed”), Danish dødsleje (“deathbed”).
Etymology from Wiktionary, CC BY-SA