Using the indefinite article with singular nouns

Singular a/an = un, uno, un', una

The Italian indefinite article (l'articolo indeterminativo) corresponds to English a/an and is used with singular nouns. It also corresponds to the number one.

Use  uno for singular masculine nouns beginning with z or s+ a consonant. Exp: uno stadio (stadium)

Use un for all other singular masculine nouns. Exp: un orso, un naso (a bear, a nose)

Use una for singular feminine nouns starting with a consonant. Exp: una matita, una canzone (a pencil, a song)

Use un' for singular feminine nouns starting with a vowel. Exp: un'ape (a bee)

Using the definite articles with nouns

 Singular The = La, Lo, Il, L'

Use 'la' for singular feminine nouns starting with a consonant. Exp: La sorella, la cugina

Use 'lo' for singular masculine nouns starting with 'Z' and 'S + a consonant'. Exp: Lo zaino, lo stato

Use 'il' for all other singular masculine nouns. Exp: Il gatto, il quadro

Use "L'" for all singular nouns that start with a vowel. Exp: L'iguana, l'orso

Plural The = Le, Gli, I, L'

Use 'le' for plural feminine nouns starting with a consonant. Exp: Le sorelle, le cugine

Use 'gli' with plural masculine nouns starting with 'Z' and 'S + a consonant'. Exp: Gli zaini, gli stati

Use 'i' for all other plural masculine nouns. Exp: I gatti, i quadri.

Use "L'" for all plural nouns that start with a vowel. Exp: L'iguane, l'orsi

Rules to make a singular noun plural

To make a singular noun ending in “o” plural, change the “o” to “i”. Here is an example; Naso (nose) to Nasi (noses)

Special note: when the “o” is preceded by an “i” you just drop the “o” and do not add a second “i”. Here is an example; Negozio (store) Negozi (stores)

To make a singular noun ending in “a” plural, change the “a” to “e”. Here is an example; Casa (house) to Case (houses)

Special note: when the “a” is preceded by an “c” or “g” you must add an “h” before the “e” in order to maintain the hard “c” or “g” sound. Here is an example; Amica (friend) Amiche (friends)

To make a singular noun ending in “e” plural, change the “e” to “i”. Here is an example;
Dottore (doctor) to Dottori (doctors)

Nouns ending with an accented vowel or a consonant are invariable and do not change. The article changes. Example;  il sport (the sport) i sport (the sports) & la città (the city) le città (the cities)