(1):

(n.) A small wingless insect, of the family Psocidae, which makes a similar but fainter sound; - called also deathtick.

(2):

(n.) The guard set over a criminal before his execution.

(3):

(n.) 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.