4-Letter Words Matching _I_O

There are 21 4-letter words that match _I_O. 9 are common words, such as CIAO and DIDO. A rarer one is JIAO. In this set, L is the most frequent open letter (8 words). 0 words contain a doubled letter.

Full list 21

ciaodidokilolidolimosilotirovinowinoficofilofinogirokinolilolinomilomisopisofidojiao

About this list

Words
21 (9 common words)
Common example
ciao
Rare example
jiao
Doubled letters
0
Ending in S
0
Most frequent letter
L (8)

Questions

How many 4-letter words matching _i_o are there?

21. 9 of them are common words.

What is a common example?

CIAO is among the common words in this set.