Nouns whose masculine and feminine are individual

These few nouns have the same root in masculine and feminine forms, but they might be considered totally individual, because masculine singular turns into masculin plural, and feminine singular into feminine plural; their meaning is generically related, sometimes as a metaphor.

 

filo (masc. sing.) = string	fili (masc. plur.) = strings
fila (fem. sing.) = row, queue	file (fem. plural) = rows, queues
peso (masc. sing.) = weight	pesi (masc. plur.) = weights
pesa (fem. sing.) = scales for heavy goods	pese (fem. plural) = scales for heavy goods (plural)
visto (masc. sing.) = visa (for passports, etc.)	visti (masc. plur.) = visas
vista (fem. sing.) = sight; view	viste (fem. plur.) = sights; views

 

NOUNS INDICATING TREES AND THEIR FRUIT

The pattern "masculine for the tree - feminine for the fruit" is used for many fruits which grow on trees (but not for fruit coming from plants or bushes, such as melons, raspberries, grapes, etc. etc.):

melo = apple-tree	mela = apple
pesco = peach-tree	pesca = peach
olivo (or ulivo) = olive-tree	oliva = olive
ciliegio = cherry-tree	ciliegia = cherry
pruno = prune-tree	prugna = prune (notice a slight change in the noun's root)

A few fruit names, though, are masculine and this pattern could be confusing. Also when the fruit's name ends with e, masculine and feminine could be told only by the article (which will be the subject of the following paragraph) or by an adjective. In these cases, the above-said pattern may not be followed, and the form albero di... (literally tree of...) is used, followed by the fruit's plural form:

 

un limone (masculine, singular) = a lemon	un limone, or un albero di limoni = a lemon-tree
una noce (feminine, singular) = a nut	un noce, or un albero di noci = a nut-tree

The latter form can be used as a standard, also in the previous case, so apple-tree could be either melo or albero di mele.

But such details are not really important at this stage, so don't worry about them now. Simply, be aware of the importance of masculine and feminine gender in Italian nouns.
A few nouns have two different plural genders, with some difference in their meaning:

 

osso (masculine, singular) = bone

ossa (feminine, plural, Latin neutre form, see above) = bones (of living beings)

ossi (masculine plural) = bones (in a more "material" sense, i.e. a bone of a T-steak)

gesto (masculine, singular) = human act, deed, or gesture

gesta (feminine, plural, Latin neutre form) = human acts, deeds

gesti (masculine plural) = gestures

 

NOUNS WHOSE SINGULAR AND PLURAL INFLECTIONS ARE THE SAME

They belong to several categories:

FOREIGN NOUNS

Italian is becoming slowly accustomed to new foreign terms, especially in technical fields; some of these terms have no actual equivalent in the original language, so they are periodically added to the standard dictionary.
Some others, though, are perfectly translatable; in these cases, the use of foreign terms is considered rather snobbish, also because in Italy the knowledge of foreign languages is still far from a good standard. Furthermore, people who like showing themselves by using foreign words are very likely to pronounce them incorrectly, or to misspell them; on the other end, when foreign words are pronounced correctly, they might even be not understood at all, a funny paradox. Therefore, if a foreign word has an Italian equivalent, it is advisable to use the latter.
Nevertheless, many international terms of common use would never create a problem.
This is how gender works in these cases.

· When the meaning of the term is similar to an Italian one, or when it has a specific gender in the original language, the noun is usually given the same gender in Italian. A few examples:

CD (compact disk) basically relates to the concept of music record (in Italian: disco, masculine), so this noun, either short form or full-length form, is considered masculine, and obviously floppy disk, hard disk, etc. are masculine too, since they contain the same concept of recording device;

metro (short form for the French métropolitaine = urban subway railway) is also used in Italian; the "official" form is metropolitana, feminine (actual translation of the French term, very similar to Italian), but the short form is also used, obviously with feminine gender.

e-mail is similar to mail (in Italian: posta, feminine), so it is usually considered feminine, although some "purists" prefer to use the actual translation posta elettronica (electronic mail);

· When the gender of the noun is more indefinite (no similarity with Italian nouns), it is usually given a standard masculine gender (which in Italian mimics the neutre gender):

sport, computer or PC, würstel, whisky, ouverture, modem, menù (also spelled menu, as in French), etc. etc.

But in their plural forms, these nouns are always treated as if they were singular:

due metro (two subways), tre menù (three menus), quattro e-mail (four e-mails), and so on.

Some people prefer to use the foreign plurals (due ouvertures, quattro e-mails, etc.): This too is considered correct, provided that the right plurals are used (for example, words of German origin cannot be turned into their plural forms by simply adding an s).