Giallo (‘yellow’) is a colour we’ve seen a lot of lately, thanks to France’s gilet gialli, or ‘yellow vests’.

But in fact, in Italy the word giallo is rarely out of the headlines.

That’s because the word is a byword for a certain type of mystery, thanks to a popular series of detective stories – usually quite short books in the pulp genre, often with unbelievable twists – that were published in the early 20th century between distinctive yellow covers.

Un giallo is still used as shorthand for ‘a detective story’ today.

A contemporary libro giallo, both literally and figuratively.

But in Italian newspaper-speak, giallo can refer to anything vaguely mysterious: like ‘riddle’ or ‘enigma’.

Most often you’ll see it accompanying crime stories, particularly when the culprit isn’t yet known.

‘Vigne Nuovo mystery solved: poisoned by girlfriend with drink and drugs, she’s arrested for murder’: a recent crime story.

It’s also used to spice up the fairly mundane. Local residents report hearing an unexplained noise? It’s un giallo. S

ports reporters aren’t sure what time a football match starts? Un giallo again. 

‘Ahead of Lazio-Roma, the time of the derby is a mystery: decision expected today’: one recent sports headline. 

Headline writers are the people most prone to use the word this way: in everyday speech, you’re more likely to hear giallo (pronounced “jial-lo”) in all the places you’d expect it – on a football pitch (un cartellino giallo is a ‘yellow card’), inside eggs (il giallo dell’uovo – ‘egg yolk’) and all over the phone book (le pagine gialle – ‘Yellow Pages’).

But there’s one extra place it turns up: on traffic lights, which for some reason in Italy turn giallo instead of orange or amber.

Why? It’s a mystery.

Do you have a favourite Italian word you’d like us to feature? If so, please email us with your suggestion.