Macchina vs. auto vs. automobile

In Italian, there are three common words used to refer to a car: 'macchina', 'auto', and 'automobile'. While they all mean 'car', they have subtle differences in usage and connotation.

Macchina

'Macchina' is the most common and informal term for car in everyday Italian speech.
Prendo la macchina per andare al lavoro.
(I take the car to go to work.)
La mia macchina è rossa.
(My car is red.)

Auto

'Auto' is a shortened form of 'automobile' and is considered slightly more formal than 'macchina'.
Ho comprato un'auto nuova.
(I bought a new car.)
Il parcheggio è pieno di auto.
(The parking lot is full of cars.)

Automobile

'Automobile' is the most formal term and is often used in official or technical contexts.
L'industria automobilistica italiana è famosa in tutto il mondo.
(The Italian automobile industry is famous worldwide.)
Il museo espone automobili d'epoca.
(The museum exhibits vintage automobiles.)

Summary

While 'macchina' is the most casual and widely used term in everyday conversation, 'auto' offers a middle ground in formality, and 'automobile' is reserved for more formal or technical situations. All three words are correct and interchangeable in most contexts, but their usage can vary depending on the speaker's preference and the situation.