"My lighter is new."
Translation:Mein Feuerzeug ist neu.
Is lighter the same pluralization as all the other zeug, is it pluralized as zeugE with an E at the end?
Is the answer supposed to have an umlaut above the first u in Feuerzeug? The answer in the original question says it's supposed to be Feürzeug but the answer here says Feuerzeug?
I was practicing on the lesson "stuff" and when I entered in my answer for this question, it corrected me and said that it was supposed to be spelled Feürzeug
If that's true, it's an error and needs to be reported. Maybe you come across it again. Modern German (newer than 200 yo) doesn't know a sound (or diphtong) "eü", you can just find this combination of letters in composita like "Lageübermittlung" where they are two independent sounds ("Lage-Übermittlung").
A very common sound shift is au -> äu, like in Haus (sg.) -> Häuser (pl.) or sauber (adj.) -> säubern (verb).
Also, the plurals of composita never change in the first word (Feuer-), but only in the second (-zeug -> -zeuge), as you would do it in English (e.g. power plant -> power plants, germ. Kraftwerk -> Kraftwerke, not powers plants and Kräftewerke).
Meine is for female or plural words, but Feuerzeug is a singular neuter.