[Allegra]

"MORTAR" - Several meanings, the one most germane to this discussion being an indirect fire infantry weapon.

What you hear when mortars are being launched in your general direction: "Incoming! Incoming! Take cover, take cover, take cover. Seek shelter in the nearest hardstand structure. If you are in a hardstand structure, shelter in place. Take cover, take cover, take cover."

Just thought I'd throw that in...

[thackney]

I understand it is not the only use for that announcement.

[kanawa]

I lived by the sewer, I died by the sewer.
Some called it mortar but I called it sewer side.

[JoeProBono]

http://www.youtube.com/user/texasgirly1979?blend=4&ob=4