child一词的复数形式是children。

The plural of 'child' is 'children'.

《牛津词典》

men一词是复数形式。

The word 'men' is plural in number.

《牛津词典》

歌剧（opera）这个词的意思是作品，实际上它是指复数形式的作品一词。

The word opera means work, actually it means works.

youdao

codexes the plural of this is,is either codexes sometimes, codices I mean,Latin,you'd use the old Latinized plural,codices.

这个词的复数可以是，你可以用旧拉丁语复数。

耶鲁公开课 - 新约课程节选

All you had to know is the word "Dog" and the plural morpheme 's' and you could put them together to create a word.

你只需知道"狗"这个词以,及复数语素'们',你可以将它们组合在一起来创造出一个词

耶鲁公开课 - 心理学导论课程节选

So the Diadokhoi, the Greek plural of Diadochi, as we often refer to it, ended up splitting his army into four parts and four dynasties descending from the four successors.

所以这四个Diadokhoi，也就是Diadochi的复数形式，我们通常用这个词，最终将他的军队分割为四个部分,由此产生了四个王朝。

耶鲁公开课 - 新约课程节选