How did the military tank get its name?

Answer 1

The name "tank" was actually a code name meant to deceive the enemy during WWI. Its origin is strange but well-documented. Like many word origins there are differing stories of how "tank" was chosen, but all play off the shape of early vehicles whose tall, cylindrical turrets made them resemble mechanized water carriers.

When Britain and France started secret development of self-powered armoured vehicles, various names were suggested including land cruisers, land ships (or landships), caterpillar machine gun destroyers, etc. The British military instead wanted a code name that was plausible and yet would hide the vehicles' true nature from German spies.

One claim is that the name "water carrier" was formally adopted. According to this narrative the head of the Landships Committee pointed out that "water carrier" would be abbreviated as "WC" - British slang for toilet! "Carrier" was quickly changed to "tank", still referring to the cylindrical turret.

A second and less-colorful claim is that the use of "tank" was nothing more than shorthand speech by the vehicles' builders. A third mixes the two stories to say it was the vehicles' builders who realised the unfortunate abbreviation and settled on "tank" as an alternative to "carrier".

Regardless, the name "tank" was in common use within months.