isaioni = grandfather (noun) (some things Google found for "isaioni": a very rare term; may mean something or be similar to some word in Italian)
Word derivation for "grandfather" :
Basque = aitona, Finnish = isoisä
Miresua = isaioni
Like my previous Miresua conlang word for "grandmother", this is a compound word. It's a combination of the Miresua words "isai" and "oni", which mean "father" and "big". I wish it didn't have three vowels in a row, but it's a valid alphabetic mixture of the Basque and Finnish words.
This Miresua conlang word has been changed. The word for "grandfather" is now "isaosa".