6-Letter Words Matching A____O

There are 18 6-letter words that match A____O. 4 are common words, such as ADAGIO and AKIMBO. A rarer one is AUSUBO. In this set, I is the most frequent open letter (9 words). 6 words contain a doubled letter.

Full list 18

adagioakimboalbinoarroyoahchooaikidoalbedoanattoapolloariosoaerugoalnicoamminoammonoaristoarsenoarsinoausubo

About this list

Words
18 (4 common words)
Common example
adagio
Rare example
ausubo
Doubled letters
6
Ending in S
0
Most frequent letter
I (9)

Questions

How many 6-letter words matching a____o are there?

18. 4 of them are common words.

What is a common example?

ADAGIO is among the common words in this set.