Instead of using adjectives to talk about size, Italian has the device of altering the noun itself, thus producing a new word. Different endings are added onto the root word. Let's look at how this works with some nouns with feminine endings.
An example of this is pentola. Una pentola is a pot. It's already pretty big, big enough for cooking pasta. Un pentolone is an even bigger pot for if you're cooking lots of pasta or canning tomatoes, as in the second example below. We could also say una pentola grande, (a big pot) but sometimes it's easier to say pentolone. So, when you hear a word that ends in -one, it's likely a large version of something that comes in various sizes.
Ci serve, naturalmente, anche qualcosa per cuocere la pasta. Una pentola, un'altra pentola per la pasta,
We also need, naturally, something for cooking the pasta. A pot, another pot for the pasta,
Captions 79-81, L'Italia a tavola Tonnarelli cacio e pepe - Part 1Play Caption
Here, a woman is describing how to make tomato sauce to can. She's going to make a big batch.
Alcuni, eh, lo fanno appassire un po' dentro i pentoloni sul fuoco...
Some, uh, cook them down a bit in big pots on the burner...
Caption 28, Giovanna spiega La passata di pomodoriPlay Caption
When the item in discussion is the smalller version, the ending -ino is typical:
E per farlo, prendiamo un pentolino come questo e ci mettiamo un pochino di olio extravergine di oliva.
And to do that we take a saucepan like this and we put a little extra virgin olive oil in it.
Captions 18-19, Marika spiega La Parmigiana di melanzane - Part 1Play Caption
Una capanna is a shack, shed, or hut. It's a feminine noun.
...oppure costruivamo una capanna con delle sedie e delle coperte
...or else we'd build a hut out of chairs and bed covers
Caption 8, Anna e Marika ricordi di infanziaPlay Caption
Un capannone can either be called a "shed," even though it's big, a "hangar," or, in the case of a mechanic's workplace, a "garage." It will have a different name in English depending on its use. It may or may not have 4 walls. It may or may not be makeshift.
...che segnalava la presenza di auto truccate in un capannone al Quadraro e trac. Va be', allora vogliamo brindare?
...that reported the presence of souped-up cars in a hangar in Quadraro, and boom. OK, so do we want to make a toast?
Captions 35-37, La Ladra EP. 8 - Il momento giusto - Part 14Play Caption
If the shack or hut is tiny, as it would be for a hunter's blind, then il capannino is the word of choice. There might be room for just one person.
Although una macchina can be any kind of machine, it's also the word for car. The more official Italian word is automobile, just like in English. The stress goes on the second O, however.
Infatti, quando ho compiuto venti anni, mi ha regalato una macchina nuova.
In fact, when I turned twenty, she got me a new car.
Captions 31-32, Adriano NonnaPlay Caption
Ci porta Giampi, che lui c'ha un macchinone.
Giampi will take us. He has a big car.
Caption 53, Sposami EP 3 - Part 7Play Caption
Sometimes the resulting word can retain the gender of the original word, as in the case of macchina.
E sotto c'era un altro cartellino bianco con disegnato su un camioncino con un gancettino che si porta via una macchinina.
And below it was another little white sign picturing a little truck with a little hook on it, which is towing a little car away.
Captions 89-91, Provaci ancora prof! S2EP1 - La finestra sulla scuola - Part 1Play Caption
As you listen to more videos, you will start noticing the endings -one and -ino. Look for the noun within the noun and you'll often be able to figure out what a word means.