The word "allowable" is an adjective, and would not have a plural. You could state that there were allowable items, or allowable actions.
* The "allowable" referred to in legal and commercial documents is a noun form, by extension, of terms such as deductible(which is also formally an adjective). In this case, the plural would use just the usual S, as "allowables".
The word allow is the verb form used with a plural subject:
We allow...
You allow...
They allow...
Parents allow...
Owners allow...
Employers allow...
The plural of allowance is allowances.
As in "his allowances were frozen".
There is no plural form for the word, countries. This word itself is a plural.
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 plural form of the word neurosis is "neuroses".
The plural form for the demonstrative pronoun this is these.
The plural form of the word "inferno" is "infernos."
The plural form of the word "ranch" is "ranches."
There is no plural form for the word, countries. This word itself is a plural.
There is no plural word for if.
The plural form is data.
The plural form of the word "baby" is "babies."
The plural form of vow is vows.
The plural form of the word "pharynx" is "pharynges."
The plural form for the word 'pioneer' is pioneers.
In Chinese, the plural form of the word "minute" is "分钟" (fēnzhōng).
The plural form for the noun valley is valleys.