I was wondering about the correct ending to use, amazing pyrotechnics or amazing pyrotechnic.
My gut-feeling says that pyrotechnics is the correct spelling, but in my native language, I've only ever seen it being spelled as a single noun. Which in turn makes me a bit puzzled.
There is no noun definition for "pyrotechnic"; it is not the singular form of "pyrotechnics". Instead, "pyrotechnics" is a collective noun which refers to multiple individual objects as a group, and which can take either singular or plural verbs depending on context. At the same time it is also treated as a mass noun (also known as "uncountable noun") so you can't have "A pyrotechnics" only "some pyrotechnics", and it also means there isn't any "more plural" form. Those two things together mean that "pyrotechnics" falls in a weird space between singular and plural both grammatically and conceptually, so it can be tricky. Using just "pyrotechnic" as a noun is incorrect though.
On the other hand, using "pyrotechnic" as an adjective is correct. Both "An amazing pyrotechnic display." and "An amazing pyrotechnics display" are equally valid and have roughly the same meaning.
I'd say "amazing pyrotechnics" is the usual form at the end of a sentence. In my experience, it's unusual to find "pyrotechnic" used in the singular, unless followed by a noun. You can check this by running a Google search for "amazing pyrotechnic".
