keyhole

keyhole

1. an aperture in a door or a lock case through which a key may be passed to engage the lock mechanism

2. a transient column of vapour or plasma formed during the welding or cutting of materials, using high energy beams, such as lasers

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

keyhole

[′kē‚hōl]

(design engineering)

A hole or a slot for receiving a key.

(metallurgy)

A welding method wherein the heat source, because of its concentration, causes a hole through the surface immediately ahead of the molten weld metal in the direction of welding; the hole is filled as the welding progresses, ensuring complete joint penetration.

(ordnance)

Of a bullet, to strike a target after tumbling in flight so that the long axis of the bullet and the line of flight are not the same; usually caused by failure of the bullet to receive sufficient spin from the rifling in the barrel.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.