What part of speech is スティール製?


What part of speech is スティール製{せい} from スティール製{せい}カテノイドexpression?  
I know スティール is a noun (steel), 製{せい} is a suffix (made of), but I don't know
their value together. スティール製{せい} is a noun or an adjective?




スティール製 works as "[a noun that can be treated as a so-called no-
adjective](https://japanese.stackexchange.com/q/2770/5010)". A native Japanese
speaker who only knows [学校文法](https://japanese.stackexchange.com/q/36310/5010)
would probably say it's a noun phrase as a whole.

Whether it's a noun or an adjective depends on how you define adjectives,
which is not easy.

  * [Why does Japanese have two kinds of adjectives? (-i adjectives and -na adjectives)](https://japanese.stackexchange.com/q/1008/5010)
  * [What is the definition of adjective in japanese?](https://japanese.stackexchange.com/q/46398/5010)




スティール製 (along with all other words using the 製 suffix) is what's sometimes
referred to as a の-adjective; essentially a grammatical noun with an
adjectival meaning.

の-adjectives can modify other nouns in the same ways that any noun can - which
is to say, by using the の particle (eg. 木製のテーブル "a wooden table") or, as in
your スティール製カテノイド example, by combining directly to form a compound noun. The の
method is more productive and can be used to describe anything, while noun
compounds are usually only used for a more limited number of established
expressions.

