All Italian nouns and adjectives have such attribute as grammatical gender. There are masculine and feminine genders in Italian language. In order to determine which gender a word belongs to, we need to look at its ending.

Italian genders

Masculine nouns end in -O
anno – year, tavolo – table, amico – friend, gatto – cat (male)
and some words on -E
ole – sun, cuore – heart, padre – father, fiore – flower and others.
Feminine nouns end in -A, -à
donna – woman, gatta – cat (female), felicità – happiness, città -city
and some words on -E
moglie – wife, madre – mother and others.
A tip: when you learn a new word that ends on -E, try to memorize which gender this word belongs to.
Masculine adjectives end in -O
bello – beautiful, brutto – igly, alto – high, basso – low
Feminine adjectives end in -A
bella – beautiful, brutta – ugly, alta – high, bassa – low
In Plural, masculine nouns and adjectives end in -i, and feminine on -e:
anno – year, anni – years
bella – beautiful, belle – beautiful (feminine, plural)
amigo – friend, amici – friends
finestra – window, finestre – windows

Italian Articles

There are articles “a” and “the” in English language, where “a” is indefinite article, and “the” is definite article.
There are indefinite and definite articles in the Italian language too.
un – masculine indefinite article, like English “a”.
una – feminine indefinite article, like English “a”
Examples:
un amico – a friend (male)
una amica – a friend (female)
un tavolo – a table
una canzone – a song
una botiglia – a bottle
un zaino – a backpack
una macchina – a car
Also, in Italian language there are indefinite articles for plural:
un becomes dei or degli, una becomes delle
We use dei when the net word starts with a consonant, and degli when the word starts with a wovel, just like with a and an in English.
Examples:
dei tavoli – tables
delle sedie – chairs
dei divani – sofas
degli amici – friends
degli uomini – men (un uomo – man)
dei libri – books
delle tazze – cups

Definitive articles.

There is the definite article “the” in English language. In Italian language we have masculine article il or lo, and feminine article la.
We use LO with words that start in Z or S.
Examples:
il biglietto – the ticket
il treno – the train
il villaggio – the village
lo zaino – the backpack
lo sbaglio – the mistake
lo zio – the uncle
la zia – the aunt
la città – the city
la conferenza – the conference
la spiaggia – the beach
Also, the article il gets shortened before vowels:
l’albero – the tree
l’amico – the friend
l’autobus – the bus
l’ufficio – the office
With plural nouns, il becomes i or gli, and la becomes le
We use i when the word starts with a consonant, and gli when the word starts with a wovel.
i giorni – the days
i nemici – the enemies
i forbici – the scissors
gli occhi – the eyes
gli uomini – the men
gli altri – the others
le porte – the doors
le ragazze – the girls
le donne – the women

Example sentences with Italian articles and genders:

I forbici costano un euro – The scissors cost 1 euro
Gli occi sono verdi – The eyes are green
Per che le porte sono chiuse? – Why the doors are closed?
Ho preparato un zaino per il viaggio – I have prepared a backpack for the travel
L’albero è molto alto – The tree is very high
Lo zio de mio amico è un calciatore famoso – The uncle of my friend is a famous soccer player
A che ora andiamo a la spiaggia? – At what time do we go to the beach?
Donde stanno le altri? – Where are the others?
Dove è un negocio in questa via? – Where is a store in this street?
Le finestre sono aperte – The windows are open
Le botiglie sono vuote – The bottles are empty
Gli alberi sono alti – The trees are high