Origin of all clear
Examples from the Web for all-clear
These all-clear fliers are filtered through special lines for expediency.How to Skip the Airport Security Line During Thanksgiving|Nina Strochlic|November 26, 2013|DAILY BEAST
After a few minutes, the soldier gave the all-clear and they kept driving.
A co-worker locked the door, and a few more tense minutes passed before the “all-clear” came.Gunman Kills Two People and Himself in Shooting at Oregon Mall|Winston Ross|December 12, 2012|DAILY BEAST
And even the blogs covering this seismic event moment by moment were reluctant to sound the all-clear.
"Think o' when the all-clear bugle sounds in Fulham," responded Bindle.Adventures of Bindle|Herbert George Jenkins
He remembered that Webster had promised to come and knock an all-clear signal on the door.The Girl on the Boat|Pelham Grenville Wodehouse
The bugles sounded All-clear in many keys all round the ear's horizon; their sound matched the waning moonlight.Living Alone|Stella Benson
When the all-clear signal sounded inside the Shed, nobody paid any attention.Space Platform|Murray Leinster