The plural form is spelt : subpoenas.
Italy does not have a plural form.
The plural form of him, her, or it is them. (objective pronouns)
The plural form of beauty is beauties.
The plural form of radius is radii.
The plural form of quiz is quizzes.
Trout is plural
The plural form of the noun 'sea' is seas.
The plural form for the noun coach is coaches.
The plural form for the noun index is indexes.
The plural form of "atlas" is "atlases."
subpoenae
The plural of "burrito" is "burritos".