In every language I know of, prepositions are pesky little critters. They cause problems way out of proportion to their small size. A case in point: the preposition da in Italian. So many different uses. The dictionary will tell you that da means "from." If only it ended there.
Let's take a look at some of these uses.
Il treno proviene da Bari.
The train is coming from Bari.
"For" in expressions of time
Aspetto da tre ore.
I've been waiting (for) three hours.
"Since" in expressions of time
Bertolli- dal 1865.
Bertolli, since 1865.
Abito a Venezia da marzo.
I've been living in Venice since March.
In historical names to denote birthplace or geographical origin
Leonardo da Vinci.
Michelangelo da Caravaggio. (although it seems now that he wasn't actually born in Caravaggio- too late)
Melozzo da Forli'
Idiomatic use for a familiar place one may go to regularly, sometimes translated by 's in English and chez in French
Basta! Torno da mia madre!
I've had enough! I'm going back to my mother!
Devo andare dal medico.
I have to go to the doctor's.
Vorrei essere al Ristorante da Romano in questo momento.
I wish I were at Da Romano Restaurant right now.
To express a characteristic of something
Roba da pazzi/matti!
That's crazy (literally, that's stuff that crazy people would do)
Si comporta da idiota.
She acts like an idiot.
To express "as" in terms of a time frame
Da giovane era molto bello.
He was very handsome when he was young/as a young man.
Cosa vuoi fare da grande?
What do you want to do when you grow up/as a big person?
To translate some uses of "by"
Quel film fu diretto da Antonioni.
That movie was directed by Antonioni.
Milano 2 fu costruito da Berlusconi.
Milano 2 was built by Berlusconi.
To express cause.
Sto morendo dal caldo.
The heat is killing me.
Function of something/someone (often noun plus noun in English)
Tazza da te'
Camera da letto.
To express value
Un biglietto da cinque (euro).
A five euro bill.
Una cosa da poco
As a sort of modal verb (should, must) with infinitive
E' una persona da evitare
This is someone who should be avoided
Un film assolutamente da vedere
A movie you absolutely must see
Used with the infinitive after nothing, something, little, much etcetera
Non ho niente da fare/bere/mangiare
I have nothing to do/drink/eat
Hai qualcosa da dirmi?
Do you have something you want to say?