Zug = (singular) platoon
Züge = (plural) platoons [note the umlaut]
Both the singular and plural can be abbreviated as Zg.
Note that the word Zug can also mean a whole lot of other things, like a (railroad) train, or (wind) draft, draw (like in pull), traction (like towing), etc. Consult a German-English dictionary.
There were no official abbreviations for many words, and people made them up as they went along. For example for Kompanie, there was Kp. and Komp.
Sometimes confusingly, is that the Germans use the "." (dot) as an ordinal indicator, (the st, nd, rd, and th added to numbers).