Until the invention of the main battle tank, tanks were typically categorized either by weight class (light, medium, heavy or superheavy tanks) or doctrinal purpose (breakthrough-, cavalry-, infantry-, cruiser-, or reconnaissance tanks). Some are larger and more thickly armoured and with large guns, while others are smaller, lightly armoured, and equipped with a smaller caliber and lighter gun. These smaller tanks move over terrain with speed and agility and can perform a reconnaissance role in addition to engaging hostile targets. The smaller, faster tank would not normally engage in battle with a larger, heavily armoured tank, except during a surprise flanking manoeuvre.
On 24 December 1915, a meeting took place at the Inter-Departmental Conference (including representatives of the Director of Naval Construction’s Committee, the Admiralty, the Ministry of Munitions, and the War Office). Its purpose was to discuss the progress of the plans for what were described as “Caterpillar Machine Gun Destroyers or Land Cruisers.” In his autobiography, Albert Gerald Stern (Secretary to the Landship Committee, later head of the Mechanical Warfare Supply Department) says that at that meeting:
Mr. (Thomas J.) Macnamara (M.P., and Parliamentary and Financial Secretary to the Admiralty) then suggested, for secrecy’s sake, to change the title of the Landship Committee. Mr. d’Eyncourt agreed that it was very desirable to retain secrecy by all means, and proposed to refer to the vessel as a “Water Carrier”. In Government offices, committees and departments are always known by their initials. For this reason I, as Secretary, considered the proposed title totally unsuitable.[a] In our search for a synonymous term, we changed the word “Water Carrier” to “Tank,” and became the “Tank Supply” or “T.S.” Committee. That is how these weapons came to be called Tanks.
He incorrectly added, “and the name has now been adopted by all countries in the world.”[5]
Lieutenant-Colonel Ernest Swinton, who was secretary to the meeting, says that he was instructed to find a non-committal word when writing his report of the proceedings. In the evening he discussed it with a fellow officer, Lt-Col Walter Dally Jones, and they chose the word “tank”. “That night, in the draft report of the conference, the word ‘tank’ was employed in its new sense for the first time.”[6] Swinton’s Notes on the Employment of Tanks, in which he uses the word throughout, was published in January 1916.