A thing or occurrence which initially causes fear, distress, etc. but which is subsequently recognized as being no cause for concern.
A warning signal (such as the call of sentry, the ringing of a bell, or the shriek of a siren) which turns out to have been given erroneously.
An obstacle, delay, disadvantage, blow (an adverse event which retards or prevents progress towards a desired outcome)
An offset to the temperature setting of a thermostat to cover a period when more or less heating is required than usual.
A step-like recession in a wall.
The required distance between a structure and a road.