Alternate (and more figurative) names for WWI tanks :
"Toad" for "Little Willie" (
he does look like a cute armoured toad to me

)
"Frogs" for British Mark I - Mark V tanks (well, obviously, as a reference to alt-LW, but also because of the
unique shape of their tracks and hull and because some British soldiers actually likened them to giant steel frogs in OTL...)
"Tabatiere" ("Cigarette Case") for the
St. Chamond tank (
well, he looks like one + a cannon, so... 
)
"Tonnelet" ("Small Barrel") for the
Renault FT-17 (it's hull generaly looks barrel-like... and I also wanted to do a little Turtledove reference...

)
"(Kampf-)Kiste" ("(Battle-)Crate") for the
Schwer Kampfwagen A7V (
seriously, just look at it...)
So... Germans coin the term Kisten instead of "Panzern" in this ATL...

Imagine
this Nazi propaganda poster with the ATL term : "Kiste. Deine Waffe !"
Russian tanks (if they would show up in combat - unlike OTL), would probably be called "vezdekhods" or "cossacks". I figure the Tsar's cossacks would be the first to acquire them, since they were one of the principal backbones of the cavalry... Or - if the early and humongous
"Tsar" tank was succesful... *shudder* "lawnmowers", "war-velocipedes"...
As for the unused American tank manufactured by Ford before the end of the war - I have no idea. Any funny suggestions ?