The plural of papyrus is papyri or papyruses. Both are acceptable, but papyri is preferred.
There is no plural form for the word, countries. This word itself is a plural.
papyri
The plural of diary is diaries.
The plural form of the word gelato is gelati.
The plural form of the word 'deed' is 'deeds'.
The noun papyrus can be countable or uncountable. In more general, commonly used, contexts, the plural form will also be papyrus. However, in more specific contexts, the plural form can also be papyri e.g. in reference to various types of papyri or a collection of papyri
The plural form for the demonstrative pronoun this is these.
The plural form of the word inferno is infernos.
The plural form is ranches.
There is no plural word for if.
There is no plural form for the word, countries. This word itself is a plural.
The plural form is data.
papyri
The plural form of the word "baby" is "babies."
The plural form for the word 'pioneer' is pioneers.
The plural form of the word "pharynx" is "pharynges."
The plural form of vow is vows.