Words not pluralized. Usually, when many a writer needs the plural form of a word, he simply adds an s, with no recourse to the rules of correct usage.

3D Printing of Near-Ambient Responsive Liquid Crystal Elastomers with Enhanced Nematic Order and Pluralized Transformation. Journal: ACS Nano Published: 2025-02-13 DOI: ...

For a compound made up of two nouns separated by a preposition, the first noun is pluralized to form the plural, as in "attorneys-at-law" and "chiefs of staff." ...