4.8 Special dual forms
Hebrew has three common words that have the unique dual ending; however, these words are usually translated as singular
שַׁמַ֫יִם heaven, sky (sometimes “heavens”)
מִצְרַ֫יִם Egypt
מַ֫יִם water (sometimes “waters”)
Additionaly, on a similar note, פָּנִים has the MP ending but it is translated as the singular “face”