deathwatch

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A vigil kept beside a dying or dead person.
• noun One who guards a condemned person before execution.
• noun A deathwatch beetle.

from The Century Dictionary.

• noun A vigil beside a dying person.
• noun A guard set over a condemned criminal for some time prior to his execution.
• noun The popular name of several small beetles which make a ticking or clicking sound, supposed by superstitious persons to be ominous of death
• noun A minute, wingless, pseudoneuropterous insect, Atropos pulsatorius, of the family Psocidæ, a great pest in botanical and entomological collections. It also makes a ticking sound.

from the GNU version of the Collaborative International Dictionary of English.

• noun A small beetle (Anobium tessellatum and other allied species). By forcibly striking its head against woodwork it makes a ticking sound, which is a call of the sexes to each other, but has been imagined by superstitious people to presage death.
• noun A small wingless insect, of the family Psocidæ, which makes a similar but fainter sound; -- called also deathtick.
• noun The guard set over a criminal before his execution.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A vigil beside a dying person
• noun One who guards a condemned person before execution.
• noun A deathwatch beetle.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun bores through wood making a ticking sound popularly thought to presage death
• noun minute wingless psocopterous insects injurious to books and papers