Lots of adjectives in Italian correspond to adjectives in English and vice versa, but sometimes an adjective form doesn't really exist in one language or the other, and a different form is used. One such form uses a (which is usually a preposition meaning "to" or "at") plus a noun. In this case, we might say this a stands for "in the manner of" or "with." It can be part of the answer to questions such as "What's it like?" "What kind is it?"
One example of this came up in this week's episode of La Ladra. It occurred in a rather banal exchange between Gina and her husband. He couldn't find his striped socks.
In English, we can say something is striped or it has stripes. In Italian, it's a bit different. We often use a.
Come dove stanno i calzini a righe?
What do you mean where are your striped socks?
Caption 3, La Ladra - Ep. 4 - Una magica bionda - Part 10 of 14
Potrebbe anche essere una tovaglia a quadretti bianchi e rossi, oppure bianchi e gialli o a grosse righe.
It could also be a red and white checked tablecloth, or else, white and yellow or with wide stripes.
Captions 4-5, Come preparare con creatività: una tavola per la campagna
In Italy, quaderni a quadretti (notebooks with grids or graph paper) are very popular. But in the U.S., unless you are using a grid for a specific purpose, like math or a making a chart, most notebooks are a righe (lined). There doesn't even seem to be a standard translation for a quadretti regarding paper. However, we asked readers to write in what they would call un quaderno a quadretti in English.
Update: Most of the people who have written in say that in English, they would call a quaderno a quadretti a "graph paper notebook." One person provided this interesting link.
Additional notes: Along with notebooks, we have notepads. The official word for this in Italian is taccuino but the more commonly-used term is a corruption of English: bloc-notes or even the pseudo-English block-notes. Make sure you pronounce the final e and s all'italiano! Let's remember that in Italian the adjective usually comes after the noun, and so notes is the kind of blocco (notebook or notepad for taking notes). A blocco is a group of similar items, so we use blocco or, when it's small, blocchetto for paper, for checks: blocchetto di assegni (checkbook).
In this lesson, we have talked about adjective equivalents. But there are adverb equivalents that use a, too, and we'll look at them in a future lesson.